更新了数据库部分的文档和代码
jackfrued
parent
c6666f45d4
commit
0953c5e58a
|
|
@ -51,15 +51,15 @@ insert into tb_emp values
|
|||
(3588, '朱九真', '会计', 5566, 2500, null, 10);
|
||||
|
||||
|
||||
-- 查询薪资最高的员工姓名和工资
|
||||
-- 查询月薪最高的员工姓名和工资
|
||||
|
||||
-- 查询员工的姓名和年薪((月薪+补贴)*12)
|
||||
-- 查询员工的姓名和年薪((月薪+补贴)*13)
|
||||
|
||||
-- 查询有员工的部门的编号和人数
|
||||
|
||||
-- 查询所有部门的名称和人数
|
||||
|
||||
-- 查询薪资最高的员工(Boss除外)的姓名和工资
|
||||
-- 查询月薪最高的员工(Boss除外)的姓名和工资
|
||||
|
||||
-- 查询薪水超过平均薪水的员工的姓名和工资
|
||||
|
||||
|
|
@ -69,24 +69,4 @@ insert into tb_emp values
|
|||
|
||||
-- 查询主管的姓名和职位
|
||||
|
||||
-- 查询薪资排名4~6名的员工姓名和工资
|
||||
|
||||
-- use hrs;
|
||||
|
||||
-- drop procedure if exists sp_avg_sal_by_dept;
|
||||
|
||||
|
||||
-- create procedure sp_avg_sal_by_dept(dno integer, out avg_sal float)
|
||||
-- begin
|
||||
-- select avg(sal) into avg_sal from tb_emp where dno=dno;
|
||||
-- end;
|
||||
|
||||
|
||||
|
||||
|
||||
-- call sp_avg_sal_by_dept(10, @avgSal);
|
||||
|
||||
-- select @avgSal;
|
||||
|
||||
|
||||
|
||||
-- 查询月薪排名4~6名的员工姓名和工资
|
||||
|
|
|
|||
|
|
@ -1,15 +0,0 @@
|
|||
drop database if exists bank;
|
||||
|
||||
create database bank default charset utf8;
|
||||
|
||||
use bank;
|
||||
|
||||
create table tb_account
|
||||
(
|
||||
accid char(8) primary key,
|
||||
accowner varchar(20) not null,
|
||||
accbalance float not null default 0
|
||||
);
|
||||
|
||||
insert into tb_account values (11223344, '王大锤', 1000);
|
||||
insert into tb_account values (22334455, '李小龙', 1000);
|
||||
|
|
@ -1,46 +0,0 @@
|
|||
drop database if exists booksys;
|
||||
|
||||
create database booksys default charset utf8;
|
||||
|
||||
use booksys;
|
||||
|
||||
create table tb_book
|
||||
(
|
||||
bookid integer not null,
|
||||
isbn char(13) not null,
|
||||
bname varchar(100) not null,
|
||||
price decimal(8,2) not null,
|
||||
author varchar(100) not null,
|
||||
publisher varchar(50) not null,
|
||||
pubdate date,
|
||||
intro varchar(500),
|
||||
lended bit default 0,
|
||||
counter integer default 0,
|
||||
primary key (bookid)
|
||||
);
|
||||
|
||||
create table tb_reader
|
||||
(
|
||||
readerid integer not null,
|
||||
rname varchar(20) not null,
|
||||
gender bit not null,
|
||||
tel char(11) not null,
|
||||
birth date,
|
||||
regdate date not null,
|
||||
available bit default 1,
|
||||
primary key (readerid)
|
||||
);
|
||||
|
||||
create table tb_record
|
||||
(
|
||||
recordid integer not null auto_increment,
|
||||
bid integer not null,
|
||||
rid integer not null,
|
||||
lenddate datetime not null,
|
||||
backdate datetime,
|
||||
pulishment decimal(6,2),
|
||||
primary key (recordid)
|
||||
);
|
||||
|
||||
alter table tb_record add constraint fk_record_bid foreign key (bid) references tb_book (bookid) on update cascade;
|
||||
alter table tb_record add constraint fk_record_rid foreign key (rid) references tb_reader (readerid) on update cascade;
|
||||
|
|
@ -1,253 +0,0 @@
|
|||
drop database if exists fangtx;
|
||||
|
||||
create database fangtx default charset utf8 collate utf8_bin;
|
||||
|
||||
use fangtx;
|
||||
|
||||
/* 创建用户表 */
|
||||
create table `tb_user`
|
||||
(
|
||||
`userid` int auto_increment comment '编号',
|
||||
`username` varchar(20) not null comment '用户名',
|
||||
`password` char(32) not null comment '用户口令',
|
||||
`realname` varchar(20) not null comment '真实姓名',
|
||||
`sex` bool default 1 comment '性别',
|
||||
`tel` varchar(20) not null comment '手机号',
|
||||
`email` varchar(255) default '' comment '邮箱',
|
||||
`regdate` datetime default now() comment '注册日期',
|
||||
`point` int default 0 comment '积分',
|
||||
`lastvisit` datetime default now() comment '最后访问时间',
|
||||
`is_authenticated` bit default 0 comment '是否认证',
|
||||
primary key (`userid`)
|
||||
);
|
||||
|
||||
/* 创建地区表 */
|
||||
create table `tb_district`
|
||||
(
|
||||
`distid` int not null comment '编号',
|
||||
`pid` int comment '父级行政单位',
|
||||
`name` varchar(255) not null comment '名称',
|
||||
`ishot` bool default 0 comment '是否为热门城市',
|
||||
`intro` varchar(255) default '' comment '介绍',
|
||||
primary key (distid)
|
||||
);
|
||||
|
||||
/* 创建经理人表 */
|
||||
create table `tb_agent`
|
||||
(
|
||||
`agentid` int not null auto_increment comment '编号',
|
||||
`name` varchar(255) not null comment '姓名',
|
||||
`tel` varchar(20) not null comment '电话',
|
||||
`servstar` int not null default 0 comment '满意度星级',
|
||||
`realstar` int not null default 0 comment '真实度星级',
|
||||
`profstar` int not null default 0 comment '专业度星级',
|
||||
`certificated` bool not null default 0 comment '是否持有专业认证',
|
||||
primary key (`agentid`)
|
||||
);
|
||||
|
||||
/* 创建用户登录日志表 */
|
||||
create table `tb_login_log`
|
||||
(
|
||||
`logid` bigint auto_increment comment '编号',
|
||||
`userid` int not null comment '用户',
|
||||
`ipaddr` varchar(255) not null comment 'IP地址',
|
||||
`logdate` datetime default now() comment '登录时间日期',
|
||||
`devcode` varchar(255) default '' comment '设备代码',
|
||||
primary key (`logid`)
|
||||
);
|
||||
|
||||
/* 创建楼盘表 */
|
||||
create table `tb_estate`
|
||||
(
|
||||
`estateid` int not null auto_increment comment '编号',
|
||||
`distid` int not null comment '所在三级行政区域',
|
||||
`name` varchar(255) not null comment '名称',
|
||||
`hot` int default 0 comment '热度',
|
||||
`intro` varchar(511) default '' comment '介绍',
|
||||
primary key (`estateid`)
|
||||
);
|
||||
|
||||
/* 创建经理人楼盘中间表 */
|
||||
create table `tb_agent_estate`
|
||||
(
|
||||
`agent_estate_id` int not null auto_increment comment '编号',
|
||||
`agentid` int not null comment '经理人',
|
||||
`estateid` int not null comment '楼盘',
|
||||
primary key (`agent_estate_id`)
|
||||
);
|
||||
|
||||
/* 创建户型表 */
|
||||
create table `tb_house_type`
|
||||
(
|
||||
`typeid` int comment '编号',
|
||||
`name` varchar(255) not null comment '名称',
|
||||
primary key (`typeid`)
|
||||
);
|
||||
|
||||
/* 创建房源信息表 */
|
||||
create table `tb_house_info`
|
||||
(
|
||||
`houseid` int not null auto_increment comment '编号',
|
||||
`title` varchar(50) not null comment '标题',
|
||||
`area` int not null comment '面积',
|
||||
`floor` int not null comment '楼层',
|
||||
`totalfloor` int not null comment '总楼层',
|
||||
`direction` varchar(10) not null comment '朝向',
|
||||
`price` int not null comment '价格',
|
||||
`priceunit` varchar(10) not null comment '价格单位',
|
||||
`detail` varchar(511) default '' comment '详情',
|
||||
`mainphoto` varchar(255) not null comment '主图',
|
||||
`pubdate` date not null comment '发布日期',
|
||||
`street` varchar(255) not null comment '街道',
|
||||
`hassubway` bool default 0 comment '是否有地铁',
|
||||
`isshared` bool default 0 comment '是否支持合租',
|
||||
`hasagentfees` bool default 0 comment '是否有中介费',
|
||||
`typeid` int not null comment '户型',
|
||||
`userid` int not null comment '发布用户',
|
||||
`distid2` int not null comment '所在二级行政区域',
|
||||
`distid3` int not null comment '所在三级行政区域',
|
||||
`estateid` int comment '楼盘',
|
||||
`agentid` int comment '经理人',
|
||||
primary key (`houseid`)
|
||||
);
|
||||
|
||||
/* 创建房源照片表 */
|
||||
create table `tb_house_photo`
|
||||
(
|
||||
`photoid` int not null auto_increment comment '编号',
|
||||
`houseid` int not null comment '房源',
|
||||
`path` varchar(255) not null comment '资源路径',
|
||||
primary key (`photoid`)
|
||||
);
|
||||
|
||||
/* 创建标签表 */
|
||||
create table `tb_tag`
|
||||
(
|
||||
`tagid` int auto_increment comment '编号',
|
||||
`content` varchar(20) not null comment '内容',
|
||||
primary key (`tagid`)
|
||||
);
|
||||
|
||||
/* 创建房源标签中间表 */
|
||||
create table `tb_house_tag`
|
||||
(
|
||||
`house_tag_id` int auto_increment comment '编号',
|
||||
`houseid` int not null comment '房源',
|
||||
`tagid` int not null comment '标签',
|
||||
primary key (`house_tag_id`)
|
||||
);
|
||||
|
||||
|
||||
/* 创建用户浏览历史记录表 */
|
||||
create table `tb_record`
|
||||
(
|
||||
`recordid` bigint auto_increment comment '编号',
|
||||
`userid` int not null comment '用户',
|
||||
`houseid` int not null comment '房源',
|
||||
`recorddate` datetime not null comment '浏览时间日期',
|
||||
primary key (`recordid`)
|
||||
);
|
||||
|
||||
/* 创建用户令牌表 */
|
||||
create table `tb_user_token`
|
||||
(
|
||||
`tokenid` int auto_increment comment '编号',
|
||||
`token` char(32) not null comment '令牌',
|
||||
`userid` int not null comment '用户',
|
||||
primary key (`tokenid`)
|
||||
);
|
||||
|
||||
/* 创建角色表 */
|
||||
create table `tb_role`
|
||||
(
|
||||
`roleid` int auto_increment comment '编号',
|
||||
`rolename` varchar(255) not null comment '角色名',
|
||||
primary key (`roleid`)
|
||||
);
|
||||
|
||||
/* 创建权限表 */
|
||||
create table `tb_privilege`
|
||||
(
|
||||
`privid` int auto_increment comment '编号',
|
||||
`method` varchar(15) not null comment '请求方法',
|
||||
`url` varchar(1024) not null comment '资源的URL',
|
||||
PRIMARY KEY (`privid`)
|
||||
);
|
||||
|
||||
/* 创建用户角色中间表 */
|
||||
create table `tb_user_role`
|
||||
(
|
||||
`urid` int auto_increment comment '编号',
|
||||
`userid` int not null comment '用户',
|
||||
`roleid` int not null comment '角色',
|
||||
primary key (`urid`)
|
||||
);
|
||||
|
||||
/* 创建角色权限中间表 */
|
||||
create table `tb_role_privilege`
|
||||
(
|
||||
`rpid` int auto_increment comment '编号',
|
||||
`roleid` int not null comment '角色',
|
||||
`privid` int not null comment '权限',
|
||||
primary key (`rpid`)
|
||||
);
|
||||
|
||||
create unique index `uni_idx_agent_estate` on `tb_agent_estate` (`agentid`, `estateid`);
|
||||
|
||||
create unique index `uni_idx_record` on `tb_record` (`userid`, `houseid`);
|
||||
|
||||
create unique index `uni_idx_userid` on `tb_user_token` (`userid`);
|
||||
|
||||
create unique index `uni_idx_username` on `tb_user` (`username`);
|
||||
|
||||
create unique index `uni_idx_tel` on `tb_user` (`tel`);
|
||||
|
||||
create unique index `uni_idx_email` on `tb_user` (`email`);
|
||||
|
||||
create unique index `uni_idx_house_tag` on `tb_house_tag` (`houseid`, `tagid`);
|
||||
|
||||
alter table `tb_agent_estate` add constraint `fk_agent_estate_agentid` foreign key (`agentid`) references `tb_agent` (`agentid`);
|
||||
|
||||
alter table `tb_agent_estate` add constraint `fk_agent_estate_estateid` foreign key (`estateid`) references `tb_estate` (`estateid`);
|
||||
|
||||
alter table `tb_district` add constraint `fk_district_pid` foreign key (`pid`) references `tb_district` (`distid`);
|
||||
|
||||
alter table `tb_estate` add constraint `fk_estate_distid` foreign key (`distid`) references `tb_district` (`distid`);
|
||||
|
||||
alter table `tb_house_info` add constraint `fk_house_info_agentid` foreign key (`agentid`) references tb_agent (`agentid`);
|
||||
|
||||
alter table `tb_house_info` add constraint `fk_house_info_distid2` foreign key (`distid2`) references tb_district (`distid`);
|
||||
|
||||
alter table `tb_house_info` add constraint `fk_house_info_distid3` foreign key (`distid3`) references tb_district (`distid`);
|
||||
|
||||
alter table `tb_house_info` add constraint `fk_house_info_estateid` foreign key (`estateid`) references tb_estate (`estateid`);
|
||||
|
||||
alter table `tb_house_info` add constraint `fk_house_info_typeid` foreign key (`typeid`) references tb_house_type (`typeid`);
|
||||
|
||||
alter table `tb_house_info` add constraint `fk_house_info_userid` foreign key (`userid`) references tb_user (`userid`);
|
||||
|
||||
alter table `tb_house_photo` add constraint `fk_house_photo_houseid` foreign key (`houseid`) references `tb_house_info` (`houseid`);
|
||||
|
||||
alter table `tb_house_tag` add constraint `fk_house_tag_houseid` foreign key (`houseid`) references `tb_house_info` (`houseid`);
|
||||
|
||||
alter table `tb_house_tag` add constraint `fk_house_tag_tagid` foreign key (`tagid`) references `tb_tag` (`tagid`);
|
||||
|
||||
alter table `tb_login_log` add constraint `fk_login_log_userid` foreign key (`userid`) references `tb_user` (`userid`);
|
||||
|
||||
alter table `tb_record` add constraint `fk_record_houseid` foreign key (`houseid`) references `tb_house_info` (`houseid`);
|
||||
|
||||
alter table `tb_record` add constraint `fk_record_userid` foreign key (`userid`) references `tb_user` (`userid`);
|
||||
|
||||
alter table `tb_user_token` add constraint `fk_token_userid` foreign key (`userid`) references `tb_user` (`userid`);
|
||||
|
||||
alter table `tb_user_role` add constraint `uni_user_role` unique (`userid`, `roleid`);
|
||||
|
||||
alter table `tb_role_privilege` add constraint `uni_role_priv` unique (`roleid`, `privid`);
|
||||
|
||||
alter table `tb_role_privilege` add constraint `fk_role_privilege_privid` foreign key (`privid`) references `tb_privilege` (`privid`);
|
||||
|
||||
alter table `tb_role_privilege` add constraint `fk_role_privilege_roleid` foreign key (`roleid`) references `tb_role` (`roleid`);
|
||||
|
||||
alter table `tb_user_role` add constraint `fk_user_role_roleid` foreign key (`roleid`) references `tb_role` (`roleid`);
|
||||
|
||||
alter table `tb_user_role` add constraint `fk_user_role_userid` foreign key (`userid`) references `tb_user` (`userid`);
|
||||
File diff suppressed because it is too large
Load Diff
|
|
@ -1,877 +0,0 @@
|
|||
<?xml version="1.0" encoding="UTF-8"?>
|
||||
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
|
||||
<plist version="1.0">
|
||||
<dict>
|
||||
<key>ContentFilters</key>
|
||||
<dict/>
|
||||
<key>auto_connect</key>
|
||||
<true/>
|
||||
<key>data</key>
|
||||
<dict>
|
||||
<key>connection</key>
|
||||
<dict>
|
||||
<key>database</key>
|
||||
<string>hrs</string>
|
||||
<key>host</key>
|
||||
<string>120.77.222.217</string>
|
||||
<key>kcid</key>
|
||||
<string>6157604644212181126</string>
|
||||
<key>name</key>
|
||||
<string>MySQL@Aliyun</string>
|
||||
<key>rdbms_type</key>
|
||||
<string>mysql</string>
|
||||
<key>sslCACertFileLocation</key>
|
||||
<string></string>
|
||||
<key>sslCACertFileLocationEnabled</key>
|
||||
<integer>0</integer>
|
||||
<key>sslCertificateFileLocation</key>
|
||||
<string></string>
|
||||
<key>sslCertificateFileLocationEnabled</key>
|
||||
<integer>0</integer>
|
||||
<key>sslKeyFileLocation</key>
|
||||
<string></string>
|
||||
<key>sslKeyFileLocationEnabled</key>
|
||||
<integer>0</integer>
|
||||
<key>type</key>
|
||||
<string>SPTCPIPConnection</string>
|
||||
<key>useSSL</key>
|
||||
<integer>0</integer>
|
||||
<key>user</key>
|
||||
<string>root</string>
|
||||
</dict>
|
||||
<key>session</key>
|
||||
<dict>
|
||||
<key>connectionEncoding</key>
|
||||
<string>utf8</string>
|
||||
<key>contentPageNumber</key>
|
||||
<integer>1</integer>
|
||||
<key>contentSelection</key>
|
||||
<data>
|
||||
YnBsaXN0MDDUAQIDBAUGOTpYJHZlcnNpb25YJG9iamVjdHNZJGFy
|
||||
Y2hpdmVyVCR0b3ASAAGGoK0HCBUWFxgZHSQoLDE2VSRudWxs0wkK
|
||||
CwwQFFdOUy5rZXlzWk5TLm9iamVjdHNWJGNsYXNzow0OD4ACgAOA
|
||||
BKMREhOABYAGgAiADFR0eXBlVHJvd3NUa2V5c18QJlNlbGVjdGlv
|
||||
bkRldGFpbFR5cGVQcmltYXJ5S2V5ZWREZXRhaWxz0wkKCxobHKCg
|
||||
gAfSHh8gIVokY2xhc3NuYW1lWCRjbGFzc2VzXxATTlNNdXRhYmxl
|
||||
RGljdGlvbmFyeaMgIiNcTlNEaWN0aW9uYXJ5WE5TT2JqZWN00goL
|
||||
JSehJoAJgAvSCykqK1lOUy5zdHJpbmeAClNlbm/SHh8tLl8QD05T
|
||||
TXV0YWJsZVN0cmluZ6MtLzBYTlNTdHJpbmdYTlNPYmplY3TSHh8y
|
||||
M15OU011dGFibGVBcnJheaMyNDVXTlNBcnJheVhOU09iamVjdNIe
|
||||
HyI3oiI4WE5TT2JqZWN0XxAPTlNLZXllZEFyY2hpdmVy0Ts8VGRh
|
||||
dGGAAQAIABEAGgAjAC0AMgA3AEUASwBSAFoAZQBsAHAAcgB0AHYA
|
||||
egB8AH4AgACCAIcAjACRALoAwQDCAMMAxQDKANUA3gD0APgBBQEO
|
||||
ARMBFQEXARkBHgEoASoBLgEzAUUBSQFSAVsBYAFvAXMBewGEAYkB
|
||||
jAGVAacBqgGvAAAAAAAAAgEAAAAAAAAAPQAAAAAAAAAAAAAAAAAA
|
||||
AbE=
|
||||
</data>
|
||||
<key>contentSortColIsAsc</key>
|
||||
<true/>
|
||||
<key>contentViewport</key>
|
||||
<string>{{0, 0}, {694, 448}}</string>
|
||||
<key>isToolbarVisible</key>
|
||||
<true/>
|
||||
<key>queries</key>
|
||||
<string>-- 注意事项：
|
||||
-- 1. 给数据库和表命名的时候尽量使用全小写
|
||||
-- 2. 作为筛选条件的字符串是否区分大小看设置的校对规则
|
||||
drop database if exists hrs;
|
||||
create database hrs default charset utf8 collate utf8_general_ci;
|
||||
|
||||
use hrs;
|
||||
|
||||
drop table if exists tb_emp;
|
||||
drop table if exists tb_dept;
|
||||
|
||||
-- 3. 数据库中的对象通常会用前缀加以区分
|
||||
-- table / view / index / function / procedure / trigger
|
||||
create table tb_dept
|
||||
(
|
||||
dno int not null comment '编号',
|
||||
dname varchar(10) not null comment '名称',
|
||||
dloc varchar(20) not null comment '所在地',
|
||||
primary key (dno)
|
||||
);
|
||||
|
||||
-- 批量插入操作
|
||||
insert into tb_dept values
|
||||
(10, '会计部', '北京'),
|
||||
(20, '研发部', '成都'),
|
||||
(30, '销售部', '重庆'),
|
||||
(40, '运维部', '深圳');
|
||||
|
||||
create table tb_emp
|
||||
(
|
||||
eno int not null comment '员工编号',
|
||||
ename varchar(20) not null comment '员工姓名',
|
||||
job varchar(20) not null comment '员工职位',
|
||||
mgr int comment '主管编号',
|
||||
sal int not null comment '员工月薪',
|
||||
comm int comment '每月补贴',
|
||||
dno int comment '所在部门编号',
|
||||
primary key (eno)
|
||||
);
|
||||
|
||||
-- 修改表添加一个列到mgr列的后面
|
||||
-- alter table tb_emp add column hiredate date after mgr;
|
||||
|
||||
-- 修改表添加一个自参照的外键约束
|
||||
-- alter table tb_emp add constraint fk_emp_mgr foreign key (mgr) references tb_emp (eno);
|
||||
|
||||
-- alter table tb_emp drop foreign key fk_emp_mgr;
|
||||
|
||||
-- alter table tb_emp drop foreign key fk_emp_dno;
|
||||
|
||||
-- restrict - 不允许操作
|
||||
-- cascade - 级联操作
|
||||
-- set null - 设置为null
|
||||
alter table tb_emp add constraint fk_emp_dno foreign key (dno) references tb_dept (dno);
|
||||
-- on delete restrict on update cascade;
|
||||
|
||||
insert into tb_emp values
|
||||
(7800, '张三丰', '总裁', null, 9000, 1200, 20),
|
||||
(2056, '乔峰', '分析师', 7800, 5000, 1500, 20),
|
||||
(3088, '李莫愁', '设计师', 2056, 3500, 800, 20),
|
||||
(3211, '张无忌', '程序员', 2056, 3200, null, 20),
|
||||
(3233, '丘处机', '程序员', 2056, 3400, null, 20),
|
||||
(3251, '张翠山', '程序员', 2056, 4000, null, 20),
|
||||
(5566, '宋远桥', '会计师', 7800, 4000, 1000, 10),
|
||||
(5234, '郭靖', '出纳', 5566, 2000, null, 10),
|
||||
(3344, '黄蓉', '销售主管', 7800, 3000, 800, 30),
|
||||
(1359, '胡一刀', '销售员', 3344, 1800, 200, 30),
|
||||
(4466, '苗人凤', '销售员', 3344, 2500, null, 30),
|
||||
(3244, '欧阳锋', '程序员', 3088, 3200, null, 20),
|
||||
(3577, '杨过', '会计', 5566, 2200, null, 10),
|
||||
(3588, '朱九真', '会计', 5566, 2500, null, 10);
|
||||
|
||||
-- 查询月薪最高的员工姓名和工资 - 子查询/嵌套查询+聚合函数
|
||||
-- select ename, sal from tb_emp order by sal desc limit 1;
|
||||
select ename, sal from tb_emp where sal=(
|
||||
select max(sal) from tb_emp
|
||||
);
|
||||
|
||||
-- 查询员工的姓名和年薪((月薪+补贴)*12)
|
||||
select ename, (sal+ifnull(comm, 0))*12 as 年薪 from tb_emp order by 年薪 desc;
|
||||
|
||||
-- 查询有员工的部门的编号和人数 - 分组查询+聚合函数
|
||||
select dno, count(dno) from tb_emp group by dno with rollup;
|
||||
|
||||
-- 查询所有部门的名称和人数 - 子查询+连接查询（左外）
|
||||
select dname as 部门名称, ifnull(total, 0) as 人数 from tb_dept t1 left join (select dno, count(dno) as total from tb_emp group by dno) t2 on t1.dno=t2.dno;
|
||||
|
||||
-- 查询月薪最高的员工(Boss除外)的姓名和工资 - 空值判断
|
||||
select ename, sal from tb_emp where sal=(select max(sal) from tb_emp where mgr is not null);
|
||||
|
||||
-- 查询月薪超过平均薪水的员工的姓名和工资
|
||||
select ename, sal from tb_emp where sal>(select avg(sal) as avgsal from tb_emp);
|
||||
|
||||
-- 查询月薪超过其所在部门平均薪水的员工的姓名、部门编号和工资
|
||||
select ename, t1.dno, sal, round(avgsal, 2) from tb_emp t1 inner join (select dno, avg(sal) as avgsal from tb_emp group by dno) t2 on t1.dno=t2.dno where sal>avgsal;
|
||||
|
||||
-- 查询部门中薪水最高的人姓名、工资和所在部门名称
|
||||
select ename, sal, dname from (select ename, sal, t1.dno from tb_emp t1 inner join (select dno, max(sal) as maxsal from tb_emp group by dno) t2 on t1.dno=t2.dno where sal=maxsal) t3 inner join tb_dept t4 on t3.dno=t4.dno;
|
||||
|
||||
-- 查询主管的姓名和职位
|
||||
select ename, job from tb_emp where eno in (select distinct mgr from tb_emp where mgr is not null);
|
||||
|
||||
-- 通常不推荐使用in或者not in集合运算和distinct去重操作
|
||||
-- 可以考虑用exists或not exists替代掉集合运算和去重操作
|
||||
select ename, job from tb_emp t1 where exists (select 'x' from tb_emp t2 where t1.eno=t2.mgr);
|
||||
|
||||
-- 查询月薪排名4~6名的员工姓名和工资
|
||||
select ename, sal from tb_emp order by sal desc limit 3, 3;
|
||||
select ename, sal from tb_emp order by sal desc limit 3 offset 3;
|
||||
|
||||
-- explain生成执行计划
|
||||
explain select eno, ename from tb_emp where eno=7800;
|
||||
explain select eno, ename from tb_emp where eno<>7900;
|
||||
explain select eno, ename from tb_emp where ename='张三丰';
|
||||
explain select eno, ename from tb_emp where ename like '张%';
|
||||
explain select eno, ename from tb_emp where ename like '%张';
|
||||
explain select eno, ename from tb_emp where ename<>'张三丰';
|
||||
|
||||
-- 视图：查询的快照（简化查询操作）
|
||||
-- 通过视图可以将用户的访问权限限制到某些指定的列上
|
||||
create view vw_emp_dept as
|
||||
select eno, ename, dname from tb_emp t1 inner join tb_dept t2 on t1.dno=t2.dno;
|
||||
|
||||
select ename, dname from vw_emp_dept;
|
||||
|
||||
drop view vw_emp_dept;
|
||||
|
||||
-- 索引（index）
|
||||
-- 索引可以加速查询所以应该在经常用于查询筛选条件的列上建立索引
|
||||
-- 索引会使用额外的存储空间而且会让增删改变得更慢（因为要更新索引）
|
||||
-- 所以不能够滥用索引
|
||||
create index idx_emp_ename on tb_emp (ename);
|
||||
drop index idx_emp_ename on tb_emp;
|
||||
|
||||
-- （存储）过程/函数：把一系列的SQL可以封装到一个过程中，而且可以加上分支和循环，将来通过过程的名字直接调用过程即可，因为创建过程时已经提前编译了SQL语句，所以比直接执行SQL语句性能更好
|
||||
|
||||
-- 重新定义定界符为$$
|
||||
delimiter $$
|
||||
|
||||
-- 创建存储过程
|
||||
create procedure sp_dept_avg_sal(deptno int, out avgsal float)
|
||||
begin
|
||||
select avg(sal) into avgsal from tb_emp where dno=deptno;
|
||||
end$$
|
||||
|
||||
-- 将定界符还原回;
|
||||
delimiter ;
|
||||
|
||||
-- 调用存储过程
|
||||
call sp_dept_avg_sal(20, @a);
|
||||
|
||||
-- 通过输出参数取出部门平均工资
|
||||
select @a;
|
||||
|
||||
-- 删除存储过程
|
||||
drop procedure sp_dept_avg_sal;
|
||||
|
||||
-- 触发器：在执行增删改操作时可以触发其他的级联操作，但是有可能导致“锁表”现象，实际开发中应该尽量避免使用触发器
|
||||
-- update tb_dept set dno=11 where dno=10;
|
||||
-- delete from tb_dept where dno=11;
|
||||
|
||||
delimiter $$
|
||||
|
||||
create trigger tr_dept_update
|
||||
after update on tb_dept for each row
|
||||
begin
|
||||
update tb_emp set dno=new.dno where dno=old.dno;
|
||||
end$$
|
||||
|
||||
delimiter ;
|
||||
|
||||
drop trigger tr_dept_update;
|
||||
|
||||
-- DCL：授予权限(grant to)和召回权限(revoke from)
|
||||
create user 'hellokitty'@'%' identified by '123123';
|
||||
|
||||
grant all privileges on hrs.* to 'hellokitty'@'%';
|
||||
|
||||
revoke insert, delete, update on hrs.* from 'hellokitty'@'%';
|
||||
|
||||
drop user 'hellokitty'@'%';
|
||||
|
||||
-- 事务（transaction）- 把多个增删改的操作做成不可分割的原子性操作
|
||||
-- 要么全部都做，要么全都不做
|
||||
|
||||
-- start transaction;
|
||||
begin;
|
||||
|
||||
delete from tb_emp;
|
||||
|
||||
|
||||
</string>
|
||||
<key>table</key>
|
||||
<string>tb_emp</string>
|
||||
<key>view</key>
|
||||
<string>SP_VIEW_CUSTOMQUERY</string>
|
||||
<key>windowVerticalDividerPosition</key>
|
||||
<real>163</real>
|
||||
</dict>
|
||||
</dict>
|
||||
<key>encrypted</key>
|
||||
<false/>
|
||||
<key>format</key>
|
||||
<string>connection</string>
|
||||
<key>queryFavorites</key>
|
||||
<array/>
|
||||
<key>queryHistory</key>
|
||||
<array>
|
||||
<string>rollback</string>
|
||||
<string>begin;
|
||||
delete from tb_emp</string>
|
||||
<string>-- 注意事项：
|
||||
-- 1. 给数据库和表命名的时候尽量使用全小写
|
||||
-- 2. 作为筛选条件的字符串是否区分大小看设置的校对规则
|
||||
drop database if exists hrs;
|
||||
create database hrs default charset utf8 collate utf8_general_ci;
|
||||
use hrs;
|
||||
drop table if exists tb_emp;
|
||||
drop table if exists tb_dept;
|
||||
-- 3. 数据库中的对象通常会用前缀加以区分
|
||||
-- table / view / index / function / procedure / trigger
|
||||
create table tb_dept
|
||||
(
|
||||
dno int not null comment '编号',
|
||||
dname varchar(10) not null comment '名称',
|
||||
dloc varchar(20) not null comment '所在地',
|
||||
primary key (dno)
|
||||
);
|
||||
-- 批量插入操作
|
||||
insert into tb_dept values
|
||||
(10, '会计部', '北京'),
|
||||
(20, '研发部', '成都'),
|
||||
(30, '销售部', '重庆'),
|
||||
(40, '运维部', '深圳');
|
||||
create table tb_emp
|
||||
(
|
||||
eno int not null comment '员工编号',
|
||||
ename varchar(20) not null comment '员工姓名',
|
||||
job varchar(20) not null comment '员工职位',
|
||||
mgr int comment '主管编号',
|
||||
sal int not null comment '员工月薪',
|
||||
comm int comment '每月补贴',
|
||||
dno int comment '所在部门编号',
|
||||
primary key (eno)
|
||||
);
|
||||
-- 修改表添加一个列到mgr列的后面
|
||||
-- alter table tb_emp add column hiredate date after mgr;
|
||||
|
||||
-- 修改表添加一个自参照的外键约束
|
||||
-- alter table tb_emp add constraint fk_emp_mgr foreign key (mgr) references tb_emp (eno);
|
||||
|
||||
-- alter table tb_emp drop foreign key fk_emp_mgr;
|
||||
|
||||
-- alter table tb_emp drop foreign key fk_emp_dno;
|
||||
|
||||
-- restrict - 不允许操作
|
||||
-- cascade - 级联操作
|
||||
-- set null - 设置为null
|
||||
alter table tb_emp add constraint fk_emp_dno foreign key (dno) references tb_dept (dno);
|
||||
-- on delete restrict on update cascade;
|
||||
|
||||
insert into tb_emp values
|
||||
(7800, '张三丰', '总裁', null, 9000, 1200, 20),
|
||||
(2056, '乔峰', '分析师', 7800, 5000, 1500, 20),
|
||||
(3088, '李莫愁', '设计师', 2056, 3500, 800, 20),
|
||||
(3211, '张无忌', '程序员', 2056, 3200, null, 20),
|
||||
(3233, '丘处机', '程序员', 2056, 3400, null, 20),
|
||||
(3251, '张翠山', '程序员', 2056, 4000, null, 20),
|
||||
(5566, '宋远桥', '会计师', 7800, 4000, 1000, 10),
|
||||
(5234, '郭靖', '出纳', 5566, 2000, null, 10),
|
||||
(3344, '黄蓉', '销售主管', 7800, 3000, 800, 30),
|
||||
(1359, '胡一刀', '销售员', 3344, 1800, 200, 30),
|
||||
(4466, '苗人凤', '销售员', 3344, 2500, null, 30),
|
||||
(3244, '欧阳锋', '程序员', 3088, 3200, null, 20),
|
||||
(3577, '杨过', '会计', 5566, 2200, null, 10),
|
||||
(3588, '朱九真', '会计', 5566, 2500, null, 10);
|
||||
-- 查询月薪最高的员工姓名和工资 - 子查询/嵌套查询+聚合函数
|
||||
-- select ename, sal from tb_emp order by sal desc limit 1;
|
||||
select ename, sal from tb_emp where sal=(
|
||||
select max(sal) from tb_emp
|
||||
);
|
||||
-- 查询员工的姓名和年薪((月薪+补贴)*12)
|
||||
select ename, (sal+ifnull(comm, 0))*12 as 年薪 from tb_emp order by 年薪 desc;
|
||||
-- 查询有员工的部门的编号和人数 - 分组查询+聚合函数
|
||||
select dno, count(dno) from tb_emp group by dno with rollup;
|
||||
-- 查询所有部门的名称和人数 - 子查询+连接查询（左外）
|
||||
select dname as 部门名称, ifnull(total, 0) as 人数 from tb_dept t1 left join (select dno, count(dno) as total from tb_emp group by dno) t2 on t1.dno=t2.dno;
|
||||
-- 查询月薪最高的员工(Boss除外)的姓名和工资 - 空值判断
|
||||
select ename, sal from tb_emp where sal=(select max(sal) from tb_emp where mgr is not null);
|
||||
-- 查询月薪超过平均薪水的员工的姓名和工资
|
||||
select ename, sal from tb_emp where sal>(select avg(sal) as avgsal from tb_emp);
|
||||
-- 查询月薪超过其所在部门平均薪水的员工的姓名、部门编号和工资
|
||||
select ename, t1.dno, sal, round(avgsal, 2) from tb_emp t1 inner join (select dno, avg(sal) as avgsal from tb_emp group by dno) t2 on t1.dno=t2.dno where sal>avgsal;
|
||||
-- 查询部门中薪水最高的人姓名、工资和所在部门名称
|
||||
select ename, sal, dname from (select ename, sal, t1.dno from tb_emp t1 inner join (select dno, max(sal) as maxsal from tb_emp group by dno) t2 on t1.dno=t2.dno where sal=maxsal) t3 inner join tb_dept t4 on t3.dno=t4.dno;
|
||||
-- 查询主管的姓名和职位
|
||||
select ename, job from tb_emp where eno in (select distinct mgr from tb_emp where mgr is not null);
|
||||
-- 通常不推荐使用in或者not in集合运算和distinct去重操作
|
||||
-- 可以考虑用exists或not exists替代掉集合运算和去重操作
|
||||
select ename, job from tb_emp t1 where exists (select 'x' from tb_emp t2 where t1.eno=t2.mgr);
|
||||
-- 查询月薪排名4~6名的员工姓名和工资
|
||||
select ename, sal from tb_emp order by sal desc limit 3, 3;
|
||||
select ename, sal from tb_emp order by sal desc limit 3 offset 3;
|
||||
-- explain生成执行计划
|
||||
explain select eno, ename from tb_emp where eno=7800;
|
||||
explain select eno, ename from tb_emp where eno<>7900;
|
||||
explain select eno, ename from tb_emp where ename='张三丰';
|
||||
explain select eno, ename from tb_emp where ename like '张%';
|
||||
explain select eno, ename from tb_emp where ename like '%张';
|
||||
explain select eno, ename from tb_emp where ename<>'张三丰';
|
||||
-- 视图：查询的快照（简化查询操作）
|
||||
-- 通过视图可以将用户的访问权限限制到某些指定的列上
|
||||
create view vw_emp_dept as
|
||||
select eno, ename, dname from tb_emp t1 inner join tb_dept t2 on t1.dno=t2.dno;
|
||||
select ename, dname from vw_emp_dept;
|
||||
drop view vw_emp_dept;
|
||||
-- 索引（index）
|
||||
-- 索引可以加速查询所以应该在经常用于查询筛选条件的列上建立索引
|
||||
-- 索引会使用额外的存储空间而且会让增删改变得更慢（因为要更新索引）
|
||||
-- 所以不能够滥用索引
|
||||
create index idx_emp_ename on tb_emp (ename);
|
||||
drop index idx_emp_ename on tb_emp;
|
||||
-- 创建存储过程
|
||||
create procedure sp_dept_avg_sal(deptno int, out avgsal float)
|
||||
begin
|
||||
select avg(sal) into avgsal from tb_emp where dno=deptno;
|
||||
end;
|
||||
-- 调用存储过程
|
||||
call sp_dept_avg_sal(20, @a);
|
||||
-- 通过输出参数取出部门平均工资
|
||||
select @a;
|
||||
-- 删除存储过程
|
||||
drop procedure sp_dept_avg_sal;
|
||||
create trigger tr_dept_update
|
||||
after update on tb_dept for each row
|
||||
begin
|
||||
update tb_emp set dno=new.dno where dno=old.dno;
|
||||
end;
|
||||
drop trigger tr_dept_update;
|
||||
-- DCL：授予权限(grant to)和召回权限(revoke from)
|
||||
create user 'hellokitty'@'%' identified by '123123';
|
||||
grant all privileges on hrs.* to 'hellokitty'@'%';
|
||||
revoke insert, delete, update on hrs.* from 'hellokitty'@'%';
|
||||
drop user 'hellokitty'@'%';
|
||||
-- 事务（transaction）- 把多个增删改的操作做成不可分割的原子性操作
|
||||
-- 要么全部都做，要么全都不做
|
||||
|
||||
-- start transaction;
|
||||
-- begin;
|
||||
|
||||
-- delete from tb_emp;
|
||||
|
||||
-- commit;
|
||||
-- rollback;</string>
|
||||
<string>-- 事务（transaction）- 把多个增删改的操作做成不可分割的原子性操作
|
||||
-- 要么全部都做，要么全都不做
|
||||
|
||||
-- start transaction;
|
||||
-- begin;
|
||||
|
||||
-- delete from tb_emp;
|
||||
|
||||
-- commit;
|
||||
-- rollback;</string>
|
||||
<string>delete from tb_emp</string>
|
||||
<string>alter table tb_emp drop foreign key fk_emp_mgr</string>
|
||||
<string>begin</string>
|
||||
<string>-- 注意事项：
|
||||
-- 1. 给数据库和表命名的时候尽量使用全小写
|
||||
-- 2. 作为筛选条件的字符串是否区分大小看设置的校对规则
|
||||
drop database if exists hrs;
|
||||
create database hrs default charset utf8 collate utf8_general_ci;
|
||||
use hrs;
|
||||
drop table if exists tb_emp;
|
||||
drop table if exists tb_dept;
|
||||
-- 3. 数据库中的对象通常会用前缀加以区分
|
||||
-- table / view / index / function / procedure / trigger
|
||||
create table tb_dept
|
||||
(
|
||||
dno int not null comment '编号',
|
||||
dname varchar(10) not null comment '名称',
|
||||
dloc varchar(20) not null comment '所在地',
|
||||
primary key (dno)
|
||||
);
|
||||
-- 批量插入操作
|
||||
insert into tb_dept values
|
||||
(10, '会计部', '北京'),
|
||||
(20, '研发部', '成都'),
|
||||
(30, '销售部', '重庆'),
|
||||
(40, '运维部', '深圳');
|
||||
create table tb_emp
|
||||
(
|
||||
eno int not null comment '员工编号',
|
||||
ename varchar(20) not null comment '员工姓名',
|
||||
job varchar(20) not null comment '员工职位',
|
||||
mgr int comment '主管编号',
|
||||
sal int not null comment '员工月薪',
|
||||
comm int comment '每月补贴',
|
||||
dno int comment '所在部门编号',
|
||||
primary key (eno)
|
||||
);
|
||||
-- 修改表添加一个列到mgr列的后面
|
||||
-- alter table tb_emp add column hiredate date after mgr;
|
||||
|
||||
-- 修改表添加一个自参照的外键约束
|
||||
alter table tb_emp add constraint fk_emp_mgr foreign key (mgr) references tb_emp (eno);
|
||||
-- alter table tb_emp drop foreign key fk_emp_dno;
|
||||
|
||||
-- restrict - 不允许操作
|
||||
-- cascade - 级联操作
|
||||
-- set null - 设置为null
|
||||
alter table tb_emp add constraint fk_emp_dno foreign key (dno) references tb_dept (dno);
|
||||
-- on delete restrict on update cascade;
|
||||
|
||||
insert into tb_emp values
|
||||
(7800, '张三丰', '总裁', null, 9000, 1200, 20),
|
||||
(2056, '乔峰', '分析师', 7800, 5000, 1500, 20),
|
||||
(3088, '李莫愁', '设计师', 2056, 3500, 800, 20),
|
||||
(3211, '张无忌', '程序员', 2056, 3200, null, 20),
|
||||
(3233, '丘处机', '程序员', 2056, 3400, null, 20),
|
||||
(3251, '张翠山', '程序员', 2056, 4000, null, 20),
|
||||
(5566, '宋远桥', '会计师', 7800, 4000, 1000, 10),
|
||||
(5234, '郭靖', '出纳', 5566, 2000, null, 10),
|
||||
(3344, '黄蓉', '销售主管', 7800, 3000, 800, 30),
|
||||
(1359, '胡一刀', '销售员', 3344, 1800, 200, 30),
|
||||
(4466, '苗人凤', '销售员', 3344, 2500, null, 30),
|
||||
(3244, '欧阳锋', '程序员', 3088, 3200, null, 20),
|
||||
(3577, '杨过', '会计', 5566, 2200, null, 10),
|
||||
(3588, '朱九真', '会计', 5566, 2500, null, 10);
|
||||
-- 查询月薪最高的员工姓名和工资 - 子查询/嵌套查询+聚合函数
|
||||
-- select ename, sal from tb_emp order by sal desc limit 1;
|
||||
select ename, sal from tb_emp where sal=(
|
||||
select max(sal) from tb_emp
|
||||
);
|
||||
-- 查询员工的姓名和年薪((月薪+补贴)*12)
|
||||
select ename, (sal+ifnull(comm, 0))*12 as 年薪 from tb_emp order by 年薪 desc;
|
||||
-- 查询有员工的部门的编号和人数 - 分组查询+聚合函数
|
||||
select dno, count(dno) from tb_emp group by dno with rollup;
|
||||
-- 查询所有部门的名称和人数 - 子查询+连接查询（左外）
|
||||
select dname as 部门名称, ifnull(total, 0) as 人数 from tb_dept t1 left join (select dno, count(dno) as total from tb_emp group by dno) t2 on t1.dno=t2.dno;
|
||||
-- 查询月薪最高的员工(Boss除外)的姓名和工资 - 空值判断
|
||||
select ename, sal from tb_emp where sal=(select max(sal) from tb_emp where mgr is not null);
|
||||
-- 查询月薪超过平均薪水的员工的姓名和工资
|
||||
select ename, sal from tb_emp where sal>(select avg(sal) as avgsal from tb_emp);
|
||||
-- 查询月薪超过其所在部门平均薪水的员工的姓名、部门编号和工资
|
||||
select ename, t1.dno, sal, round(avgsal, 2) from tb_emp t1 inner join (select dno, avg(sal) as avgsal from tb_emp group by dno) t2 on t1.dno=t2.dno where sal>avgsal;
|
||||
-- 查询部门中薪水最高的人姓名、工资和所在部门名称
|
||||
select ename, sal, dname from (select ename, sal, t1.dno from tb_emp t1 inner join (select dno, max(sal) as maxsal from tb_emp group by dno) t2 on t1.dno=t2.dno where sal=maxsal) t3 inner join tb_dept t4 on t3.dno=t4.dno;
|
||||
-- 查询主管的姓名和职位
|
||||
select ename, job from tb_emp where eno in (select distinct mgr from tb_emp where mgr is not null);
|
||||
-- 通常不推荐使用in或者not in集合运算和distinct去重操作
|
||||
-- 可以考虑用exists或not exists替代掉集合运算和去重操作
|
||||
select ename, job from tb_emp t1 where exists (select 'x' from tb_emp t2 where t1.eno=t2.mgr);
|
||||
-- 查询月薪排名4~6名的员工姓名和工资
|
||||
select ename, sal from tb_emp order by sal desc limit 3, 3;
|
||||
select ename, sal from tb_emp order by sal desc limit 3 offset 3;
|
||||
-- explain生成执行计划
|
||||
explain select eno, ename from tb_emp where eno=7800;
|
||||
explain select eno, ename from tb_emp where eno<>7900;
|
||||
explain select eno, ename from tb_emp where ename='张三丰';
|
||||
explain select eno, ename from tb_emp where ename like '张%';
|
||||
explain select eno, ename from tb_emp where ename like '%张';
|
||||
explain select eno, ename from tb_emp where ename<>'张三丰';
|
||||
-- 视图：查询的快照（简化查询操作）
|
||||
-- 通过视图可以将用户的访问权限限制到某些指定的列上
|
||||
create view vw_emp_dept as
|
||||
select eno, ename, dname from tb_emp t1 inner join tb_dept t2 on t1.dno=t2.dno;
|
||||
select ename, dname from vw_emp_dept;
|
||||
drop view vw_emp_dept;
|
||||
-- 索引（index）
|
||||
-- 索引可以加速查询所以应该在经常用于查询筛选条件的列上建立索引
|
||||
-- 索引会使用额外的存储空间而且会让增删改变得更慢（因为要更新索引）
|
||||
-- 所以不能够滥用索引
|
||||
create index idx_emp_ename on tb_emp (ename);
|
||||
drop index idx_emp_ename on tb_emp;
|
||||
-- 创建存储过程
|
||||
create procedure sp_dept_avg_sal(deptno int, out avgsal float)
|
||||
begin
|
||||
select avg(sal) into avgsal from tb_emp where dno=deptno;
|
||||
end;
|
||||
-- 调用存储过程
|
||||
call sp_dept_avg_sal(20, @a);
|
||||
-- 通过输出参数取出部门平均工资
|
||||
select @a;
|
||||
-- 删除存储过程
|
||||
drop procedure sp_dept_avg_sal;
|
||||
create trigger tr_dept_update
|
||||
after update on tb_dept for each row
|
||||
begin
|
||||
update tb_emp set dno=new.dno where dno=old.dno;
|
||||
end;
|
||||
drop trigger tr_dept_update;
|
||||
-- DCL：授予权限(grant to)和召回权限(revoke from)
|
||||
create user 'hellokitty'@'%' identified by '123123';
|
||||
grant all privileges on hrs.* to 'hellokitty'@'%';
|
||||
revoke insert, delete, update on hrs.* from 'hellokitty'@'%';
|
||||
drop user 'hellokitty'@'%'</string>
|
||||
<string>drop user 'hellokitty'@'%'</string>
|
||||
<string>-- 注意事项：
|
||||
-- 1. 给数据库和表命名的时候尽量使用全小写
|
||||
-- 2. 作为筛选条件的字符串是否区分大小看设置的校对规则
|
||||
drop database if exists hrs;
|
||||
create database hrs default charset utf8 collate utf8_general_ci;
|
||||
use hrs;
|
||||
drop table if exists tb_emp;
|
||||
drop table if exists tb_dept;
|
||||
-- 3. 数据库中的对象通常会用前缀加以区分
|
||||
-- table / view / index / function / procedure / trigger
|
||||
create table tb_dept
|
||||
(
|
||||
dno int not null comment '编号',
|
||||
dname varchar(10) not null comment '名称',
|
||||
dloc varchar(20) not null comment '所在地',
|
||||
primary key (dno)
|
||||
);
|
||||
-- 批量插入操作
|
||||
insert into tb_dept values
|
||||
(10, '会计部', '北京'),
|
||||
(20, '研发部', '成都'),
|
||||
(30, '销售部', '重庆'),
|
||||
(40, '运维部', '深圳');
|
||||
create table tb_emp
|
||||
(
|
||||
eno int not null comment '员工编号',
|
||||
ename varchar(20) not null comment '员工姓名',
|
||||
job varchar(20) not null comment '员工职位',
|
||||
mgr int comment '主管编号',
|
||||
sal int not null comment '员工月薪',
|
||||
comm int comment '每月补贴',
|
||||
dno int comment '所在部门编号',
|
||||
primary key (eno)
|
||||
);
|
||||
-- 修改表添加一个列到mgr列的后面
|
||||
-- alter table tb_emp add column hiredate date after mgr;
|
||||
|
||||
-- 修改表添加一个自参照的外键约束
|
||||
alter table tb_emp add constraint fk_emp_mgr foreign key (mgr) references tb_emp (eno);
|
||||
-- alter table tb_emp drop foreign key fk_emp_dno;
|
||||
|
||||
-- restrict - 不允许操作
|
||||
-- cascade - 级联操作
|
||||
-- set null - 设置为null
|
||||
alter table tb_emp add constraint fk_emp_dno foreign key (dno) references tb_dept (dno);
|
||||
-- on delete restrict on update cascade;
|
||||
|
||||
insert into tb_emp values
|
||||
(7800, '张三丰', '总裁', null, 9000, 1200, 20),
|
||||
(2056, '乔峰', '分析师', 7800, 5000, 1500, 20),
|
||||
(3088, '李莫愁', '设计师', 2056, 3500, 800, 20),
|
||||
(3211, '张无忌', '程序员', 2056, 3200, null, 20),
|
||||
(3233, '丘处机', '程序员', 2056, 3400, null, 20),
|
||||
(3251, '张翠山', '程序员', 2056, 4000, null, 20),
|
||||
(5566, '宋远桥', '会计师', 7800, 4000, 1000, 10),
|
||||
(5234, '郭靖', '出纳', 5566, 2000, null, 10),
|
||||
(3344, '黄蓉', '销售主管', 7800, 3000, 800, 30),
|
||||
(1359, '胡一刀', '销售员', 3344, 1800, 200, 30),
|
||||
(4466, '苗人凤', '销售员', 3344, 2500, null, 30),
|
||||
(3244, '欧阳锋', '程序员', 3088, 3200, null, 20),
|
||||
(3577, '杨过', '会计', 5566, 2200, null, 10),
|
||||
(3588, '朱九真', '会计', 5566, 2500, null, 10);
|
||||
-- 查询月薪最高的员工姓名和工资 - 子查询/嵌套查询+聚合函数
|
||||
-- select ename, sal from tb_emp order by sal desc limit 1;
|
||||
select ename, sal from tb_emp where sal=(
|
||||
select max(sal) from tb_emp
|
||||
);
|
||||
-- 查询员工的姓名和年薪((月薪+补贴)*12)
|
||||
select ename, (sal+ifnull(comm, 0))*12 as 年薪 from tb_emp order by 年薪 desc;
|
||||
-- 查询有员工的部门的编号和人数 - 分组查询+聚合函数
|
||||
select dno, count(dno) from tb_emp group by dno with rollup;
|
||||
-- 查询所有部门的名称和人数 - 子查询+连接查询（左外）
|
||||
select dname as 部门名称, ifnull(total, 0) as 人数 from tb_dept t1 left join (select dno, count(dno) as total from tb_emp group by dno) t2 on t1.dno=t2.dno;
|
||||
-- 查询月薪最高的员工(Boss除外)的姓名和工资 - 空值判断
|
||||
select ename, sal from tb_emp where sal=(select max(sal) from tb_emp where mgr is not null);
|
||||
-- 查询月薪超过平均薪水的员工的姓名和工资
|
||||
select ename, sal from tb_emp where sal>(select avg(sal) as avgsal from tb_emp);
|
||||
-- 查询月薪超过其所在部门平均薪水的员工的姓名、部门编号和工资
|
||||
select ename, t1.dno, sal, round(avgsal, 2) from tb_emp t1 inner join (select dno, avg(sal) as avgsal from tb_emp group by dno) t2 on t1.dno=t2.dno where sal>avgsal;
|
||||
-- 查询部门中薪水最高的人姓名、工资和所在部门名称
|
||||
select ename, sal, dname from (select ename, sal, t1.dno from tb_emp t1 inner join (select dno, max(sal) as maxsal from tb_emp group by dno) t2 on t1.dno=t2.dno where sal=maxsal) t3 inner join tb_dept t4 on t3.dno=t4.dno;
|
||||
-- 查询主管的姓名和职位
|
||||
select ename, job from tb_emp where eno in (select distinct mgr from tb_emp where mgr is not null);
|
||||
-- 通常不推荐使用in或者not in集合运算和distinct去重操作
|
||||
-- 可以考虑用exists或not exists替代掉集合运算和去重操作
|
||||
select ename, job from tb_emp t1 where exists (select 'x' from tb_emp t2 where t1.eno=t2.mgr);
|
||||
-- 查询月薪排名4~6名的员工姓名和工资
|
||||
select ename, sal from tb_emp order by sal desc limit 3, 3;
|
||||
select ename, sal from tb_emp order by sal desc limit 3 offset 3;
|
||||
-- explain生成执行计划
|
||||
explain select eno, ename from tb_emp where eno=7800;
|
||||
explain select eno, ename from tb_emp where eno<>7900;
|
||||
explain select eno, ename from tb_emp where ename='张三丰';
|
||||
explain select eno, ename from tb_emp where ename like '张%';
|
||||
explain select eno, ename from tb_emp where ename like '%张';
|
||||
explain select eno, ename from tb_emp where ename<>'张三丰';
|
||||
-- 视图：查询的快照（简化查询操作）
|
||||
-- 通过视图可以将用户的访问权限限制到某些指定的列上
|
||||
create view vw_emp_dept as
|
||||
select eno, ename, dname from tb_emp t1 inner join tb_dept t2 on t1.dno=t2.dno;
|
||||
select ename, dname from vw_emp_dept;
|
||||
drop view vw_emp_dept;
|
||||
-- 索引（index）
|
||||
-- 索引可以加速查询所以应该在经常用于查询筛选条件的列上建立索引
|
||||
-- 索引会使用额外的存储空间而且会让增删改变得更慢（因为要更新索引）
|
||||
-- 所以不能够滥用索引
|
||||
create index idx_emp_ename on tb_emp (ename);
|
||||
drop index idx_emp_ename on tb_emp;
|
||||
-- 创建存储过程
|
||||
create procedure sp_dept_avg_sal(deptno int, out avgsal float)
|
||||
begin
|
||||
select avg(sal) into avgsal from tb_emp where dno=deptno;
|
||||
end;
|
||||
-- 调用存储过程
|
||||
call sp_dept_avg_sal(20, @a);
|
||||
-- 通过输出参数取出部门平均工资
|
||||
select @a;
|
||||
-- 删除存储过程
|
||||
drop procedure sp_dept_avg_sal;
|
||||
create trigger tr_dept_update
|
||||
after update on tb_dept for each row
|
||||
begin
|
||||
update tb_emp set dno=new.dno where dno=old.dno;
|
||||
end;
|
||||
drop trigger tr_dept_update;
|
||||
-- DCL：授予权限(grant to)和召回权限(revoke from)
|
||||
create user 'hellokitty'@'%' identified by '123123'</string>
|
||||
<string>-- 注意事项：
|
||||
-- 1. 给数据库和表命名的时候尽量使用全小写
|
||||
-- 2. 作为筛选条件的字符串是否区分大小看设置的校对规则
|
||||
drop database if exists hrs;
|
||||
create database hrs default charset utf8 collate utf8_general_ci;
|
||||
use hrs;
|
||||
drop table if exists tb_emp;
|
||||
drop table if exists tb_dept;
|
||||
-- 3. 数据库中的对象通常会用前缀加以区分
|
||||
-- table / view / index / function / procedure / trigger
|
||||
create table tb_dept
|
||||
(
|
||||
dno int not null comment '编号',
|
||||
dname varchar(10) not null comment '名称',
|
||||
dloc varchar(20) not null comment '所在地',
|
||||
primary key (dno)
|
||||
);
|
||||
-- 批量插入操作
|
||||
insert into tb_dept values
|
||||
(10, '会计部', '北京'),
|
||||
(20, '研发部', '成都'),
|
||||
(30, '销售部', '重庆'),
|
||||
(40, '运维部', '深圳');
|
||||
create table tb_emp
|
||||
(
|
||||
eno int not null comment '员工编号',
|
||||
ename varchar(20) not null comment '员工姓名',
|
||||
job varchar(20) not null comment '员工职位',
|
||||
mgr int comment '主管编号',
|
||||
sal int not null comment '员工月薪',
|
||||
comm int comment '每月补贴',
|
||||
dno int comment '所在部门编号',
|
||||
primary key (eno)
|
||||
);
|
||||
-- 修改表添加一个列到mgr列的后面
|
||||
-- alter table tb_emp add column hiredate date after mgr;
|
||||
|
||||
-- 修改表添加一个自参照的外键约束
|
||||
alter table tb_emp add constraint fk_emp_mgr foreign key (mgr) references tb_emp (eno);
|
||||
-- alter table tb_emp drop foreign key fk_emp_dno;
|
||||
|
||||
-- restrict - 不允许操作
|
||||
-- cascade - 级联操作
|
||||
-- set null - 设置为null
|
||||
alter table tb_emp add constraint fk_emp_dno foreign key (dno) references tb_dept (dno);
|
||||
-- on delete restrict on update cascade;
|
||||
|
||||
insert into tb_emp values
|
||||
(7800, '张三丰', '总裁', null, 9000, 1200, 20),
|
||||
(2056, '乔峰', '分析师', 7800, 5000, 1500, 20),
|
||||
(3088, '李莫愁', '设计师', 2056, 3500, 800, 20),
|
||||
(3211, '张无忌', '程序员', 2056, 3200, null, 20),
|
||||
(3233, '丘处机', '程序员', 2056, 3400, null, 20),
|
||||
(3251, '张翠山', '程序员', 2056, 4000, null, 20),
|
||||
(5566, '宋远桥', '会计师', 7800, 4000, 1000, 10),
|
||||
(5234, '郭靖', '出纳', 5566, 2000, null, 10),
|
||||
(3344, '黄蓉', '销售主管', 7800, 3000, 800, 30),
|
||||
(1359, '胡一刀', '销售员', 3344, 1800, 200, 30),
|
||||
(4466, '苗人凤', '销售员', 3344, 2500, null, 30),
|
||||
(3244, '欧阳锋', '程序员', 3088, 3200, null, 20),
|
||||
(3577, '杨过', '会计', 5566, 2200, null, 10),
|
||||
(3588, '朱九真', '会计', 5566, 2500, null, 10);
|
||||
-- 查询月薪最高的员工姓名和工资 - 子查询/嵌套查询+聚合函数
|
||||
-- select ename, sal from tb_emp order by sal desc limit 1;
|
||||
select ename, sal from tb_emp where sal=(
|
||||
select max(sal) from tb_emp
|
||||
);
|
||||
-- 查询员工的姓名和年薪((月薪+补贴)*12)
|
||||
select ename, (sal+ifnull(comm, 0))*12 as 年薪 from tb_emp order by 年薪 desc;
|
||||
-- 查询有员工的部门的编号和人数 - 分组查询+聚合函数
|
||||
select dno, count(dno) from tb_emp group by dno with rollup;
|
||||
-- 查询所有部门的名称和人数 - 子查询+连接查询（左外）
|
||||
select dname as 部门名称, ifnull(total, 0) as 人数 from tb_dept t1 left join (select dno, count(dno) as total from tb_emp group by dno) t2 on t1.dno=t2.dno;
|
||||
-- 查询月薪最高的员工(Boss除外)的姓名和工资 - 空值判断
|
||||
select ename, sal from tb_emp where sal=(select max(sal) from tb_emp where mgr is not null);
|
||||
-- 查询月薪超过平均薪水的员工的姓名和工资
|
||||
select ename, sal from tb_emp where sal>(select avg(sal) as avgsal from tb_emp);
|
||||
-- 查询月薪超过其所在部门平均薪水的员工的姓名、部门编号和工资
|
||||
select ename, t1.dno, sal, round(avgsal, 2) from tb_emp t1 inner join (select dno, avg(sal) as avgsal from tb_emp group by dno) t2 on t1.dno=t2.dno where sal>avgsal;
|
||||
-- 查询部门中薪水最高的人姓名、工资和所在部门名称
|
||||
select ename, sal, dname from (select ename, sal, t1.dno from tb_emp t1 inner join (select dno, max(sal) as maxsal from tb_emp group by dno) t2 on t1.dno=t2.dno where sal=maxsal) t3 inner join tb_dept t4 on t3.dno=t4.dno;
|
||||
-- 查询主管的姓名和职位
|
||||
select ename, job from tb_emp where eno in (select distinct mgr from tb_emp where mgr is not null);
|
||||
-- 通常不推荐使用in或者not in集合运算和distinct去重操作
|
||||
-- 可以考虑用exists或not exists替代掉集合运算和去重操作
|
||||
select ename, job from tb_emp t1 where exists (select 'x' from tb_emp t2 where t1.eno=t2.mgr);
|
||||
-- 查询月薪排名4~6名的员工姓名和工资
|
||||
select ename, sal from tb_emp order by sal desc limit 3, 3;
|
||||
select ename, sal from tb_emp order by sal desc limit 3 offset 3;
|
||||
-- explain生成执行计划
|
||||
explain select eno, ename from tb_emp where eno=7800;
|
||||
explain select eno, ename from tb_emp where eno<>7900;
|
||||
explain select eno, ename from tb_emp where ename='张三丰';
|
||||
explain select eno, ename from tb_emp where ename like '张%';
|
||||
explain select eno, ename from tb_emp where ename like '%张';
|
||||
explain select eno, ename from tb_emp where ename<>'张三丰';
|
||||
-- 视图：查询的快照（简化查询操作）
|
||||
-- 通过视图可以将用户的访问权限限制到某些指定的列上
|
||||
create view vw_emp_dept as
|
||||
select eno, ename, dname from tb_emp t1 inner join tb_dept t2 on t1.dno=t2.dno;
|
||||
select ename, dname from vw_emp_dept;
|
||||
drop view vw_emp_dept;
|
||||
-- 索引（index）
|
||||
-- 索引可以加速查询所以应该在经常用于查询筛选条件的列上建立索引
|
||||
-- 索引会使用额外的存储空间而且会让增删改变得更慢（因为要更新索引）
|
||||
-- 所以不能够滥用索引
|
||||
create index idx_emp_ename on tb_emp (ename);
|
||||
drop index idx_emp_ename on tb_emp;
|
||||
-- 创建存储过程
|
||||
create procedure sp_dept_avg_sal(deptno int, out avgsal float)
|
||||
begin
|
||||
select avg(sal) into avgsal from tb_emp where dno=deptno;
|
||||
end;
|
||||
-- 调用存储过程
|
||||
call sp_dept_avg_sal(20, @a);
|
||||
-- 通过输出参数取出部门平均工资
|
||||
select @a;
|
||||
-- 删除存储过程
|
||||
drop procedure sp_dept_avg_sal;
|
||||
-- 触发器：在执行增删改操作时可以触发其他的级联操作，但是有可能导致“锁表”现象，实际开发中应该尽量避免使用触发器
|
||||
update tb_dept set dno=11 where dno=10</string>
|
||||
<string>-- 注意事项：
|
||||
-- 1. 给数据库和表命名的时候尽量使用全小写
|
||||
-- 2. 作为筛选条件的字符串是否区分大小看设置的校对规则
|
||||
drop database if exists hrs;
|
||||
create database hrs default charset utf8 collate utf8_general_ci;
|
||||
use hrs;
|
||||
drop table if exists tb_emp;
|
||||
drop table if exists tb_dept;
|
||||
-- 3. 数据库中的对象通常会用前缀加以区分
|
||||
-- table / view / index / function / procedure / trigger
|
||||
create table tb_dept
|
||||
(
|
||||
dno int not null comment '编号',
|
||||
dname varchar(10) not null comment '名称',
|
||||
dloc varchar(20) not null comment '所在地',
|
||||
primary key (dno)
|
||||
);
|
||||
-- 批量插入操作
|
||||
insert into tb_dept values
|
||||
(10, '会计部', '北京'),
|
||||
(20, '研发部', '成都'),
|
||||
(30, '销售部', '重庆'),
|
||||
(40, '运维部', '深圳');
|
||||
create table tb_emp
|
||||
(
|
||||
eno int not null comment '员工编号',
|
||||
ename varchar(20) not null comment '员工姓名',
|
||||
job varchar(20) not null comment '员工职位',
|
||||
mgr int comment '主管编号',
|
||||
sal int not null comment '员工月薪',
|
||||
comm int comment '每月补贴',
|
||||
dno int comment '所在部门编号',
|
||||
primary key (eno)
|
||||
);
|
||||
-- 修改表添加一个列到mgr列的后面
|
||||
-- alter table tb_emp add column hiredate date after mgr;
|
||||
|
||||
-- 修改表添加一个自参照的外键约束
|
||||
alter table tb_emp add constraint fk_emp_mgr foreign key (mgr) references tb_emp (eno);
|
||||
alter table tb_emp drop foreign key fk_emp_dno</string>
|
||||
<string>revoke insert, delete, update on hrs.* from 'hellokitty'@'%'</string>
|
||||
<string>grant all privileges on hrs.* to 'hellokitty'@'%'</string>
|
||||
<string>-- DCL：授予权限(grant to)和召回权限(revoke from)
|
||||
create user 'hellokitty'@'%' identified by '123123'</string>
|
||||
<string>delete from tb_dept where dno=11</string>
|
||||
<string>update tb_dept set dno=11 where dno=10</string>
|
||||
<string>alter table tb_emp add constraint fk_emp_dno foreign key (dno) references tb_dept (dno) on delete cascade on update cascade</string>
|
||||
<string>alter table tb_emp drop foreign key fk_emp_dno</string>
|
||||
<string>delete from tb_dept where dno=10</string>
|
||||
</array>
|
||||
<key>rdbms_type</key>
|
||||
<string>mysql</string>
|
||||
<key>rdbms_version</key>
|
||||
<string>5.5.60-MariaDB</string>
|
||||
<key>version</key>
|
||||
<integer>1</integer>
|
||||
</dict>
|
||||
</plist>
|
||||
|
|
@ -1,480 +0,0 @@
|
|||
<?xml version="1.0" encoding="UTF-8"?>
|
||||
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
|
||||
<plist version="1.0">
|
||||
<dict>
|
||||
<key>ContentFilters</key>
|
||||
<dict/>
|
||||
<key>auto_connect</key>
|
||||
<true/>
|
||||
<key>data</key>
|
||||
<dict>
|
||||
<key>connection</key>
|
||||
<dict>
|
||||
<key>host</key>
|
||||
<string>120.77.222.217</string>
|
||||
<key>kcid</key>
|
||||
<string>6157604644212181126</string>
|
||||
<key>name</key>
|
||||
<string>MySQL@Aliyun</string>
|
||||
<key>rdbms_type</key>
|
||||
<string>mysql</string>
|
||||
<key>sslCACertFileLocation</key>
|
||||
<string></string>
|
||||
<key>sslCACertFileLocationEnabled</key>
|
||||
<integer>0</integer>
|
||||
<key>sslCertificateFileLocation</key>
|
||||
<string></string>
|
||||
<key>sslCertificateFileLocationEnabled</key>
|
||||
<integer>0</integer>
|
||||
<key>sslKeyFileLocation</key>
|
||||
<string></string>
|
||||
<key>sslKeyFileLocationEnabled</key>
|
||||
<integer>0</integer>
|
||||
<key>type</key>
|
||||
<string>SPTCPIPConnection</string>
|
||||
<key>useSSL</key>
|
||||
<integer>0</integer>
|
||||
<key>user</key>
|
||||
<string>root</string>
|
||||
</dict>
|
||||
<key>session</key>
|
||||
<dict>
|
||||
<key>connectionEncoding</key>
|
||||
<string>utf8</string>
|
||||
<key>contentPageNumber</key>
|
||||
<integer>1</integer>
|
||||
<key>contentSelection</key>
|
||||
<data>
|
||||
YnBsaXN0MDDUAQIDBAUGJSZYJHZlcnNpb25YJG9iamVjdHNZJGFy
|
||||
Y2hpdmVyVCR0b3ASAAGGoKgHCBMUFRYaIVUkbnVsbNMJCgsMDxJX
|
||||
TlMua2V5c1pOUy5vYmplY3RzViRjbGFzc6INDoACgAOiEBGABIAF
|
||||
gAdUdHlwZVRyb3dzXxAdU2VsZWN0aW9uRGV0YWlsVHlwZU5TSW5k
|
||||
ZXhTZXTSFwsYGVxOU1JhbmdlQ291bnQQAIAG0hscHR5aJGNsYXNz
|
||||
bmFtZVgkY2xhc3Nlc1pOU0luZGV4U2V0oh8gWk5TSW5kZXhTZXRY
|
||||
TlNPYmplY3TSGxwiI1xOU0RpY3Rpb25hcnmiIiRYTlNPYmplY3Rf
|
||||
EA9OU0tleWVkQXJjaGl2ZXLRJyhUZGF0YYABAAgAEQAaACMALQAy
|
||||
ADcAQABGAE0AVQBgAGcAagBsAG4AcQBzAHUAdwB8AIEAoQCmALMA
|
||||
tQC3ALwAxwDQANsA3gDpAPIA9wEEAQcBEAEiASUBKgAAAAAAAAIB
|
||||
AAAAAAAAACkAAAAAAAAAAAAAAAAAAAEs
|
||||
</data>
|
||||
<key>contentSortColIsAsc</key>
|
||||
<true/>
|
||||
<key>contentViewport</key>
|
||||
<string>{{0, 0}, {694, 448}}</string>
|
||||
<key>isToolbarVisible</key>
|
||||
<true/>
|
||||
<key>queries</key>
|
||||
<string>-- 如果存在名为school的数据库就删除它
|
||||
drop database if exists school;
|
||||
|
||||
-- 创建名为school的数据库并设置默认的字符集和排序方式
|
||||
create database school default charset utf8 collate utf8_bin;
|
||||
|
||||
-- 切换到school数据库上下文环境
|
||||
use school;
|
||||
|
||||
-- 创建学院表
|
||||
create table tb_college
|
||||
(
|
||||
collid int not null auto_increment comment '编号',
|
||||
collname varchar(50) not null comment '名称',
|
||||
collmaster varchar(20) not null comment '院长',
|
||||
collweb varchar(511) default '' comment '网站',
|
||||
primary key (collid)
|
||||
);
|
||||
|
||||
-- 创建学生表
|
||||
create table tb_student
|
||||
(
|
||||
stuid int not null comment '学号',
|
||||
stuname varchar(20) not null comment '姓名',
|
||||
stusex bit default 1 comment '性别',
|
||||
stubirth date not null comment '出生日期',
|
||||
stuaddr varchar(255) default '' comment '籍贯',
|
||||
collid int not null comment '所属学院',
|
||||
primary key (stuid),
|
||||
foreign key (collid) references tb_college (collid)
|
||||
);
|
||||
|
||||
-- alter table tb_student add constraint fk_student_collid foreign key (collid) references tb_college (collid);
|
||||
|
||||
-- 创建教师表
|
||||
create table tb_teacher
|
||||
(
|
||||
teaid int not null comment '工号',
|
||||
teaname varchar(20) not null comment '姓名',
|
||||
teatitle varchar(10) default '助教' comment '职称',
|
||||
collid int not null comment '所属学院',
|
||||
primary key (teaid),
|
||||
foreign key (collid) references tb_college (collid)
|
||||
);
|
||||
|
||||
-- 创建课程表
|
||||
create table tb_course
|
||||
(
|
||||
couid int not null comment '编号',
|
||||
couname varchar(50) not null comment '名称',
|
||||
coucredit int not null comment '学分',
|
||||
teaid int not null comment '授课老师',
|
||||
primary key (couid),
|
||||
foreign key (teaid) references tb_teacher (teaid)
|
||||
);
|
||||
|
||||
-- 创建选课记录表
|
||||
create table tb_score
|
||||
(
|
||||
scid int auto_increment comment '选课记录编号',
|
||||
stuid int not null comment '选课学生',
|
||||
couid int not null comment '所选课程',
|
||||
scdate datetime comment '选课时间日期',
|
||||
scmark decimal(4,1) comment '考试成绩',
|
||||
primary key (scid),
|
||||
foreign key (stuid) references tb_student (stuid),
|
||||
foreign key (couid) references tb_course (couid)
|
||||
);
|
||||
|
||||
-- 添加唯一性约束（一个学生选某个课程只能选一次）
|
||||
alter table tb_score add constraint uni_score_stuid_couid unique (stuid, couid);
|
||||
|
||||
-- 插入学院数据
|
||||
insert into tb_college (collname, collmaster, collweb) values
|
||||
('计算机学院', '左冷禅', 'http://www.abc.com'),
|
||||
('外国语学院', '岳不群', 'http://www.xyz.com'),
|
||||
('经济管理学院', '风清扬', 'http://www.foo.com');
|
||||
|
||||
-- 插入学生数据
|
||||
insert into tb_student (stuid, stuname, stusex, stubirth, stuaddr, collid) values
|
||||
(1001, '杨逍', 1, '1990-3-4', '四川成都', 1),
|
||||
(1002, '任我行', 1, '1992-2-2', '湖南长沙', 1),
|
||||
(1033, '王语嫣', 0, '1989-12-3', '四川成都', 1),
|
||||
(1572, '岳不群', 1, '1993-7-19', '陕西咸阳', 1),
|
||||
(1378, '纪嫣然', 0, '1995-8-12', '四川绵阳', 1),
|
||||
(1954, '林平之', 1, '1994-9-20', '福建莆田', 1),
|
||||
(2035, '东方不败', 1, '1988-6-30', null, 2),
|
||||
(3011, '林震南', 1, '1985-12-12', '福建莆田', 3),
|
||||
(3755, '项少龙', 1, '1993-1-25', null, 3),
|
||||
(3923, '杨不悔', 0, '1985-4-17', '四川成都', 3);
|
||||
|
||||
-- 插入老师数据
|
||||
insert into tb_teacher (teaid, teaname, teatitle, collid) values
|
||||
(1122, '张三丰', '教授', 1),
|
||||
(1133, '宋远桥', '副教授', 1),
|
||||
(1144, '杨逍', '副教授', 1),
|
||||
(2255, '范遥', '副教授', 2),
|
||||
(3366, '韦一笑', '讲师', 3);
|
||||
|
||||
-- 插入课程数据
|
||||
insert into tb_course (couid, couname, coucredit, teaid) values
|
||||
(1111, 'Python程序设计', 3, 1122),
|
||||
(2222, 'Web前端开发', 2, 1122),
|
||||
(3333, '操作系统', 4, 1122),
|
||||
(4444, '计算机网络', 2, 1133),
|
||||
(5555, '编译原理', 4, 1144),
|
||||
(6666, '算法和数据结构', 3, 1144),
|
||||
(7777, '经贸法语', 3, 2255),
|
||||
(8888, '成本会计', 2, 3366),
|
||||
(9999, '审计学', 3, 3366);
|
||||
|
||||
-- 插入选课数据
|
||||
insert into tb_score (stuid, couid, scdate, scmark) values
|
||||
(1001, 1111, '2017-09-01', 95),
|
||||
(1001, 2222, '2017-09-01', 87.5),
|
||||
(1001, 3333, '2017-09-01', 100),
|
||||
(1001, 4444, '2018-09-03', null),
|
||||
(1001, 6666, '2017-09-02', 100),
|
||||
(1002, 1111, '2017-09-03', 65),
|
||||
(1002, 5555, '2017-09-01', 42),
|
||||
(1033, 1111, '2017-09-03', 92.5),
|
||||
(1033, 4444, '2017-09-01', 78),
|
||||
(1033, 5555, '2017-09-01', 82.5),
|
||||
(1572, 1111, '2017-09-02', 78),
|
||||
(1378, 1111, '2017-09-05', 82),
|
||||
(1378, 7777, '2017-09-02', 65.5),
|
||||
(2035, 7777, '2018-09-03', 88),
|
||||
(2035, 9999, curdate(), null),
|
||||
(3755, 1111, date(now()), null),
|
||||
(3755, 8888, date(now()), null),
|
||||
(3755, 9999, '2017-09-01', 92);
|
||||
|
||||
-- 查询所有学生信息
|
||||
select * from tb_student;
|
||||
|
||||
-- 查询所有课程名称及学分(投影和别名)
|
||||
select couname, coucredit from tb_course;
|
||||
select couname as 课程名称, coucredit as 学分 from tb_course;
|
||||
|
||||
select stuname as 姓名, case stusex when 1 then '男' else '女' end as 性别 from tb_student;
|
||||
select stuname as 姓名, if(stusex, '男', '女') as 性别 from tb_student;
|
||||
|
||||
-- 查询所有女学生的姓名和出生日期(筛选)
|
||||
select stuname, stubirth from tb_student where stusex=0;
|
||||
|
||||
-- 查询所有80后学生的姓名、性别和出生日期(筛选)
|
||||
select stuname, stusex, stubirth from tb_student where stubirth>='1980-1-1' and stubirth<='1989-12-31';
|
||||
select stuname, stusex, stubirth from tb_student where stubirth between '1980-1-1' and '1989-12-31';
|
||||
|
||||
-- 查询姓"杨"的学生姓名和性别(模糊)
|
||||
select stuname, stusex from tb_student where stuname like '杨%';
|
||||
|
||||
-- 查询姓"杨"名字两个字的学生姓名和性别(模糊)
|
||||
select stuname, stusex from tb_student where stuname like '杨_';
|
||||
|
||||
-- 查询姓"杨"名字三个字的学生姓名和性别(模糊)
|
||||
select stuname, stusex from tb_student where stuname like '杨__';
|
||||
|
||||
-- 查询名字中有"不"字或"嫣"字的学生的姓名(模糊)
|
||||
select stuname, stusex from tb_student where stuname like '%不%' or stuname like '%嫣%';
|
||||
|
||||
-- 查询没有录入家庭住址的学生姓名(空值)
|
||||
select stuname from tb_student where stuaddr is null;
|
||||
|
||||
-- 查询录入了家庭住址的学生姓名(空值)
|
||||
select stuname from tb_student where stuaddr is not null;
|
||||
|
||||
-- 查询学生选课的所有日期(去重)
|
||||
select distinct scdate from tb_score;
|
||||
|
||||
-- 查询学生的家庭住址(去重)
|
||||
select distinct stuaddr from tb_student where stuaddr is not null;
|
||||
|
||||
-- 查询男学生的姓名和生日按年龄从大到小排列(排序)
|
||||
-- asc - ascending - 升序（从小到大）
|
||||
-- desc - descending - 降序（从大到小）
|
||||
select stuname as 姓名, year(now())-year(stubirth) as 年龄 from tb_student where stusex=1 order by 年龄 desc;
|
||||
|
||||
-- 聚合函数：max / min / count / sum / avg
|
||||
-- 查询年龄最大的学生的出生日期(聚合函数)
|
||||
select min(stubirth) from tb_student;
|
||||
|
||||
-- 查询年龄最小的学生的出生日期(聚合函数)
|
||||
select max(stubirth) from tb_student;
|
||||
|
||||
-- 查询男女学生的人数(分组和聚合函数)
|
||||
select count(stuid) from tb_student;
|
||||
select stusex, count(*) from tb_student group by stusex;
|
||||
select stusex, min(stubirth) from tb_student group by stusex;
|
||||
|
||||
-- 查询课程编号为1111的课程的平均成绩(筛选和聚合函数)
|
||||
select avg(scmark) from tb_score where couid=1111;
|
||||
select min(scmark) from tb_score where couid=1111;
|
||||
select count(scid) from tb_score where couid=1111;
|
||||
select count(scmark) from tb_score where couid=1111;
|
||||
|
||||
-- 查询学号为1001的学生所有课程的平均分(筛选和聚合函数)
|
||||
select avg(scmark) from tb_score where stuid=1001;
|
||||
|
||||
-- 查询每个学生的学号和平均成绩(分组和聚合函数)
|
||||
select stuid as 学号, avg(scmark) as 平均分 from tb_score group by stuid;
|
||||
|
||||
-- 查询平均成绩大于等于90分的学生的学号和平均成绩
|
||||
-- 分组以前的筛选使用where子句
|
||||
-- 分组以后的筛选使用having子句
|
||||
select stuid as 学号, avg(scmark) as 平均分 from tb_score group by stuid having 平均分>=90;
|
||||
|
||||
-- 查询年龄最大的学生的姓名(子查询/嵌套的查询)
|
||||
select stuname from tb_student where stubirth=(
|
||||
select min(stubirth) from tb_student
|
||||
);
|
||||
|
||||
-- 查询年龄最大的学生姓名和年龄(子查询+运算)
|
||||
select stuname as 姓名, year(now())-year(stubirth) as 年龄 from tb_student where stubirth=(
|
||||
select min(stubirth) from tb_student
|
||||
);
|
||||
|
||||
-- 查询选了两门以上的课程的学生姓名(子查询/分组条件/集合运算)
|
||||
explain select stuname from tb_student where stuid in (
|
||||
select stuid from tb_score group by stuid having count(stuid)>2
|
||||
)
|
||||
|
||||
-- 查询学生姓名、课程名称以及成绩(连接查询)
|
||||
select stuname, couname, scmark from tb_student t1, tb_course t2, tb_score t3 where t1.stuid=t3.stuid and t2.couid=t3.couid and scmark is not null;
|
||||
|
||||
select stuname, couname, scmark from tb_student t1 inner join tb_score t3 on t1.stuid=t3.stuid inner join tb_course t2 on t2.couid=t3.couid where scmark is not null order by scmark desc limit 5 offset 10;
|
||||
|
||||
select stuname, couname, scmark from tb_student t1 inner join tb_score t3 on t1.stuid=t3.stuid inner join tb_course t2 on t2.couid=t3.couid where scmark is not null order by scmark desc limit 10, 5;
|
||||
|
||||
-- 单表：65535TB
|
||||
-- 单列：4G - LONGBLOB (Binary Large OBject) / LONGTEXT
|
||||
-- 查询选课学生的姓名和平均成绩(子查询和连接查询)
|
||||
select stuname, avgmark from tb_student t1, (select stuid, avg(scmark) as avgmark from tb_score group by stuid) t2 where t1.stuid=t2.stuid;
|
||||
|
||||
select stuname, avgmark from tb_student t1 inner join
|
||||
(select stuid, avg(scmark) as avgmark from tb_score group by stuid) t2 on t1.stuid=t2.stuid;
|
||||
|
||||
-- 内连接（inner join）：只有满足连接条件的记录才会被查出来
|
||||
-- 外连接（outer join）：左外连接 / 右外连接 / 全外连接
|
||||
-- left outer join / right outer join / full outer join
|
||||
-- 查询每个学生的姓名和选课数量(左外连接和子查询)
|
||||
select stuname, ifnull(total, 0) from tb_student t1 left outer join (select stuid, count(stuid) as total from tb_score group by stuid) t2 on t1.stuid=t2.stuid;
|
||||
</string>
|
||||
<key>view</key>
|
||||
<string>SP_VIEW_CUSTOMQUERY</string>
|
||||
<key>windowVerticalDividerPosition</key>
|
||||
<real>163</real>
|
||||
</dict>
|
||||
</dict>
|
||||
<key>encrypted</key>
|
||||
<false/>
|
||||
<key>format</key>
|
||||
<string>connection</string>
|
||||
<key>queryFavorites</key>
|
||||
<array/>
|
||||
<key>queryHistory</key>
|
||||
<array>
|
||||
<string>-- 查询选了两门以上的课程的学生姓名(子查询/分组条件/集合运算)
|
||||
explain select stuname from tb_student where stuid=any(
|
||||
select stuid from tb_score group by stuid having count(stuid)>2
|
||||
)</string>
|
||||
<string>explain select stuname from tb_student where stuid in (
|
||||
select stuid from tb_score group by stuid having count(stuid)>2
|
||||
)</string>
|
||||
<string>select stuname from tb_student where stuid in (
|
||||
select stuid from tb_score group by stuid having count(stuid)>2
|
||||
)</string>
|
||||
<string>select stuname from tb_student where stuid=(
|
||||
select stuid from tb_score group by stuid having count(stuid)>2
|
||||
)</string>
|
||||
<string>-- 如果存在名为school的数据库就删除它
|
||||
drop database if exists school;
|
||||
-- 创建名为school的数据库并设置默认的字符集和排序方式
|
||||
create database school default charset utf8 collate utf8_bin;
|
||||
-- 切换到school数据库上下文环境
|
||||
use school;
|
||||
-- 创建学院表
|
||||
create table tb_college
|
||||
(
|
||||
collid int not null auto_increment comment '编号',
|
||||
collname varchar(50) not null comment '名称',
|
||||
collmaster varchar(20) not null comment '院长',
|
||||
collweb varchar(511) default '' comment '网站',
|
||||
primary key (collid)
|
||||
);
|
||||
-- 创建学生表
|
||||
create table tb_student
|
||||
(
|
||||
stuid int not null comment '学号',
|
||||
stuname varchar(20) not null comment '姓名',
|
||||
stusex bit default 1 comment '性别',
|
||||
stubirth date not null comment '出生日期',
|
||||
stuaddr varchar(255) default '' comment '籍贯',
|
||||
collid int not null comment '所属学院',
|
||||
primary key (stuid),
|
||||
foreign key (collid) references tb_college (collid)
|
||||
);
|
||||
-- alter table tb_student add constraint fk_student_collid foreign key (collid) references tb_college (collid);
|
||||
|
||||
-- 创建教师表
|
||||
create table tb_teacher
|
||||
(
|
||||
teaid int not null comment '工号',
|
||||
teaname varchar(20) not null comment '姓名',
|
||||
teatitle varchar(10) default '助教' comment '职称',
|
||||
collid int not null comment '所属学院',
|
||||
primary key (teaid),
|
||||
foreign key (collid) references tb_college (collid)
|
||||
);
|
||||
-- 创建课程表
|
||||
create table tb_course
|
||||
(
|
||||
couid int not null comment '编号',
|
||||
couname varchar(50) not null comment '名称',
|
||||
coucredit int not null comment '学分',
|
||||
teaid int not null comment '授课老师',
|
||||
primary key (couid),
|
||||
foreign key (teaid) references tb_teacher (teaid)
|
||||
);
|
||||
-- 创建选课记录表
|
||||
create table tb_score
|
||||
(
|
||||
scid int auto_increment comment '选课记录编号',
|
||||
stuid int not null comment '选课学生',
|
||||
couid int not null comment '所选课程',
|
||||
scdate datetime comment '选课时间日期',
|
||||
scmark decimal(4,1) comment '考试成绩',
|
||||
primary key (scid),
|
||||
foreign key (stuid) references tb_student (stuid),
|
||||
foreign key (couid) references tb_course (couid)
|
||||
);
|
||||
-- 添加唯一性约束（一个学生选某个课程只能选一次）
|
||||
alter table tb_score add constraint uni_score_stuid_couid unique (stuid, couid);
|
||||
-- 插入学院数据
|
||||
insert into tb_college (collname, collmaster, collweb) values
|
||||
('计算机学院', '左冷禅', 'http://www.abc.com'),
|
||||
('外国语学院', '岳不群', 'http://www.xyz.com'),
|
||||
('经济管理学院', '风清扬', 'http://www.foo.com');
|
||||
-- 插入学生数据
|
||||
insert into tb_student (stuid, stuname, stusex, stubirth, stuaddr, collid) values
|
||||
(1001, '杨逍', 1, '1990-3-4', '四川成都', 1),
|
||||
(1002, '任我行', 1, '1992-2-2', '湖南长沙', 1),
|
||||
(1033, '王语嫣', 0, '1989-12-3', '四川成都', 1),
|
||||
(1572, '岳不群', 1, '1993-7-19', '陕西咸阳', 1),
|
||||
(1378, '纪嫣然', 0, '1995-8-12', '四川绵阳', 1),
|
||||
(1954, '林平之', 1, '1994-9-20', '福建莆田', 1),
|
||||
(2035, '东方不败', 1, '1988-6-30', null, 2),
|
||||
(3011, '林震南', 1, '1985-12-12', '福建莆田', 3),
|
||||
(3755, '项少龙', 1, '1993-1-25', null, 3),
|
||||
(3923, '杨不悔', 0, '1985-4-17', '四川成都', 3);
|
||||
-- 插入老师数据
|
||||
insert into tb_teacher (teaid, teaname, teatitle, collid) values
|
||||
(1122, '张三丰', '教授', 1),
|
||||
(1133, '宋远桥', '副教授', 1),
|
||||
(1144, '杨逍', '副教授', 1),
|
||||
(2255, '范遥', '副教授', 2),
|
||||
(3366, '韦一笑', '讲师', 3);
|
||||
-- 插入课程数据
|
||||
insert into tb_course (couid, couname, coucredit, teaid) values
|
||||
(1111, 'Python程序设计', 3, 1122),
|
||||
(2222, 'Web前端开发', 2, 1122),
|
||||
(3333, '操作系统', 4, 1122),
|
||||
(4444, '计算机网络', 2, 1133),
|
||||
(5555, '编译原理', 4, 1144),
|
||||
(6666, '算法和数据结构', 3, 1144),
|
||||
(7777, '经贸法语', 3, 2255),
|
||||
(8888, '成本会计', 2, 3366),
|
||||
(9999, '审计学', 3, 3366);
|
||||
-- 插入选课数据
|
||||
insert into tb_score (stuid, couid, scdate, scmark) values
|
||||
(1001, 1111, '2017-09-01', 95),
|
||||
(1001, 2222, '2017-09-01', 87.5),
|
||||
(1001, 3333, '2017-09-01', 100),
|
||||
(1001, 4444, '2018-09-03', null),
|
||||
(1001, 6666, '2017-09-02', 100),
|
||||
(1002, 1111, '2017-09-03', 65),
|
||||
(1002, 5555, '2017-09-01', 42),
|
||||
(1033, 1111, '2017-09-03', 92.5),
|
||||
(1033, 4444, '2017-09-01', 78),
|
||||
(1033, 5555, '2017-09-01', 82.5),
|
||||
(1572, 1111, '2017-09-02', 78),
|
||||
(1378, 1111, '2017-09-05', 82),
|
||||
(1378, 7777, '2017-09-02', 65.5),
|
||||
(2035, 7777, '2018-09-03', 88),
|
||||
(2035, 9999, curdate(), null),
|
||||
(3755, 1111, date(now()), null),
|
||||
(3755, 8888, date(now()), null),
|
||||
(3755, 9999, '2017-09-01', 92)</string>
|
||||
<string>select stuname, couname, scmark from tb_student t1 inner join tb_score t3 on t1.stuid=t3.stuid inner join tb_course t2 on t2.couid=t3.couid where scmark is not null order by scmark desc limit 5 offset 10</string>
|
||||
<string>select stuname, couname, scmark from tb_student t1 inner join tb_score t3 on t1.stuid=t3.stuid inner join tb_course t2 on t2.couid=t3.couid where scmark is not null order by scmark desc limit 10, 5</string>
|
||||
<string>select stuname, couname, scmark from tb_student t1 inner join tb_score t3 on t1.stuid=t3.stuid inner join tb_course t2 on t2.couid=t3.couid where scmark is not null order by scmark desc limit 5, 5</string>
|
||||
<string>select stuname, couname, scmark from tb_student t1 inner join tb_score t3 on t1.stuid=t3.stuid inner join tb_course t2 on t2.couid=t3.couid where scmark is not null order by scmark desc limit 50, 5</string>
|
||||
<string>select stuname, couname, scmark from tb_student t1 inner join tb_score t3 on t1.stuid=t3.stuid inner join tb_course t2 on t2.couid=t3.couid where scmark is not null order by scmark desc limit 5 offset 5</string>
|
||||
<string>select stuname, couname, scmark from tb_student t1 inner join tb_score t3 on t1.stuid=t3.stuid inner join tb_course t2 on t2.couid=t3.couid where scmark is not null order by scmark desc limit 5</string>
|
||||
<string>select stuname, couname, scmark from tb_student t1 inner join tb_score t3 on t1.stuid=t3.stuid inner join tb_course t2 on t2.couid=t3.couid where scmark is not null order by scmark desc</string>
|
||||
<string>select stuname, couname, scmark from tb_student t1 inner join tb_score t3 on t1.stuid=t3.stuid inner join tb_course t2 on t2.couid=t3.couid where scmark is not null</string>
|
||||
<string>select stuname, couname, scmark from tb_student t1, tb_course t2, tb_score t3 where t1.stuid=t3.stuid and t2.couid=t3.couid and scmark is not null</string>
|
||||
<string>select stuname, couname, scmark from tb_student t1, tb_course t2, tb_score t3 where t1.stuid=t3.stuid and t2.couid=t3.couid where scmark is not null</string>
|
||||
<string>-- 查询学生姓名、课程名称以及成绩(连接查询)
|
||||
select stuname, couname, scmark from tb_student t1, tb_course t2, tb_score t3 where t1.stuid=t3.stuid and t2.couid=t3.couid where scmark is not null</string>
|
||||
<string>select stuname, avgmark from tb_student t1 inner join
|
||||
(select stuid, avg(scmark) as avgmark from tb_score group by stuid) t2 on t1.stuid=t2.stuid</string>
|
||||
<string>select stuname, avgmark from tb_student t1, (select stuid, avg(scmark) as avgmark from tb_score group by stuid) t2 where t1.stuid=t2.stuid</string>
|
||||
<string>select stuname, ifnull(total, 0) from tb_student t1 left outer join (select stuid, count(stuid) as total from tb_score group by stuid) t2 on t1.stuid=t2.stuid</string>
|
||||
<string>select stuname, ifnull(total,0) from tb_student t1 left outer join (select stuid, count(stuid) as total from tb_score group by stuid) t2 on t1.stuid=t2.stuid</string>
|
||||
</array>
|
||||
<key>rdbms_type</key>
|
||||
<string>mysql</string>
|
||||
<key>rdbms_version</key>
|
||||
<string>5.7.26</string>
|
||||
<key>version</key>
|
||||
<integer>1</integer>
|
||||
</dict>
|
||||
</plist>
|
||||
|
|
@ -350,16 +350,14 @@
|
|||
select stuname from tb_student where stuaddr is not null;
|
||||
|
||||
-- 查询学生选课的所有日期(去重)
|
||||
select distinct scdate from tb_score;
|
||||
select distinct seldate from tb_record;
|
||||
|
||||
-- 查询学生的家庭住址(去重)
|
||||
select distinct stuaddr from tb_student where stuaddr is not null;
|
||||
|
||||
-- 查询男学生的姓名和生日按年龄从大到小排列(排序)
|
||||
-- asc (ascending) - 升序（从小到大）/ desc (descending) - 降序（从大到小）
|
||||
select stuname as 姓名, year(now())-year(stubirth) as 年龄 from tb_student where stusex=1 order by 年龄 desc;
|
||||
select stuname as 姓名, datediff(curdate(), stubirth) div 365 as 年龄 from tb_student where stusex=1 order by 年龄 desc;
|
||||
|
||||
-- 聚合函数：max / min / count / sum / avg
|
||||
-- 查询年龄最大的学生的出生日期(聚合函数)
|
||||
select min(stubirth) from tb_student;
|
||||
|
||||
|
|
@ -370,51 +368,42 @@
|
|||
select stusex, count(*) from tb_student group by stusex;
|
||||
|
||||
-- 查询课程编号为1111的课程的平均成绩(筛选和聚合函数)
|
||||
select avg(scmark) from tb_score where couid=1111;
|
||||
select avg(score) from tb_record where cid=1111;
|
||||
|
||||
-- 查询学号为1001的学生所有课程的平均分(筛选和聚合函数)
|
||||
select avg(scmark) from tb_score where stuid=1001;
|
||||
select avg(score) from tb_record where sid=1001;
|
||||
|
||||
-- 查询每个学生的学号和平均成绩(分组和聚合函数)
|
||||
select stuid as 学号, avg(scmark) as 平均分 from tb_score group by stuid;
|
||||
select sid as 学号, avg(score) as 平均分 from tb_record group by sid;
|
||||
|
||||
-- 查询平均成绩大于等于90分的学生的学号和平均成绩
|
||||
-- 分组以前的筛选使用where子句 / 分组以后的筛选使用having子句
|
||||
select stuid as 学号, avg(scmark) as 平均分 from tb_score group by stuid having 平均分>=90;
|
||||
select sid as 学号, avg(score) as 平均分 from tb_record group by sid having 平均分>=90;
|
||||
|
||||
-- 查询年龄最大的学生的姓名(子查询/嵌套的查询)
|
||||
select stuname from tb_student where stubirth=(
|
||||
select min(stubirth) from tb_student
|
||||
);
|
||||
select stuname from tb_student where stubirth=( select min(stubirth) from tb_student );
|
||||
|
||||
-- 查询年龄最大的学生姓名和年龄(子查询+运算)
|
||||
select stuname as 姓名, year(now())-year(stubirth) as 年龄 from tb_student where stubirth=(
|
||||
select min(stubirth) from tb_student
|
||||
);
|
||||
select stuname as 姓名, datediff(curdate(), stubirth) div 365 as 年龄 from tb_student where stubirth=( select min(stubirth) from tb_student );
|
||||
|
||||
-- 查询选了两门以上的课程的学生姓名(子查询/分组条件/集合运算)
|
||||
select stuname from tb_student where stuid in (
|
||||
select stuid from tb_score group by stuid having count(stuid)>2
|
||||
)
|
||||
select stuname from tb_student where stuid in ( select stuid from tb_record group by stuid having count(stuid)>2 );
|
||||
|
||||
-- 查询学生姓名、课程名称以及成绩(连接查询)
|
||||
select stuname, couname, scmark from tb_student t1, tb_course t2, tb_score t3 where t1.stuid=t3.stuid and t2.couid=t3.couid and scmark is not null;
|
||||
select stuname, couname, score from tb_student t1, tb_course t2, tb_record t3 where stuid=sid and couid=cid and score is not null;
|
||||
|
||||
-- 查询学生姓名、课程名称以及成绩按成绩从高到低查询第11-15条记录(内连接+分页)
|
||||
select stuname, couname, scmark from tb_student t1 inner join tb_score t3 on t1.stuid=t3.stuid inner join tb_course t2 on t2.couid=t3.couid where scmark is not null order by scmark desc limit 5 offset 10;
|
||||
select stuname, couname, score from tb_student inner join tb_record on stuid=sid inner join tb_course on couid=cid where score is not null order by score desc limit 5 offset 10;
|
||||
|
||||
select stuname, couname, scmark from tb_student t1 inner join tb_score t3 on t1.stuid=t3.stuid inner join tb_course t2 on t2.couid=t3.couid where scmark is not null order by scmark desc limit 10, 5;
|
||||
select stuname, couname, score from tb_student inner join tb_record on stuid=sid inner join tb_course on couid=cid where score is not null order by score desc limit 10, 5;
|
||||
|
||||
-- 查询选课学生的姓名和平均成绩(子查询和连接查询)
|
||||
select stuname, avgmark from tb_student t1, (select stuid, avg(scmark) as avgmark from tb_score group by stuid) t2 where t1.stuid=t2.stuid;
|
||||
select stuname, avgmark from tb_student, ( select sid, avg(score) as avgmark from tb_record group by sid ) temp where stuid=sid;
|
||||
|
||||
select stuname, avgmark from tb_student t1 inner join
|
||||
(select stuid, avg(scmark) as avgmark from tb_score group by stuid) t2 on t1.stuid=t2.stuid;
|
||||
select stuname, avgmark from tb_student inner join ( select sid, avg(score) as avgmark from tb_record group by sid ) temp on stuid=sid;
|
||||
|
||||
-- 内连接（inner join）- 只有满足连接条件的记录才会被查出来
|
||||
-- 外连接（outer join）- 左外连接(left outer join) / 右外连接(right outer join) / 全外连接
|
||||
-- 查询每个学生的姓名和选课数量(左外连接和子查询)
|
||||
select stuname, ifnull(total, 0) from tb_student t1 left outer join (select stuid, count(stuid) as total from tb_score group by stuid) t2 on t1.stuid=t2.stuid;
|
||||
select stuname, ifnull(total, 0) from tb_student left outer join ( select sid, count(sid) as total from tb_record group by sid ) temp on stuid=sid;
|
||||
```
|
||||
|
||||
4. DCL
|
||||
|
|
|
|||
|
|
@ -1,4 +1,3 @@
|
|||
## 日志和调试
|
||||
|
||||
|
||||
|
||||
在项目开发阶段，显示足够的调试信息以辅助开发人员调试代码还是非常必要的.
|
||||
|
|
|
|||
Loading…
Reference in New Issue