mysql 基础（子查询）

子查询：

1）列子查询

select * from emp where managerid  in (select id from emp where dept_id=1)

2）行子查询

: 查询与“张无忌”的薪资及直属领导相同的员工信息

select * from emp where (salary, managerid) = (select salary, managerid from emp where name='张无忌');

3）表子查询

 1. 查询与user1 user2的职称和薪资相同的员工信息

select * from emp where (job, salary) in (select job, salary from emp where name='user1' or name='user2')

 2. 查询入职时间在 ‘2020-01-05’之后的员工及其部门信息 (from之后的子查询)

select e.*, d.* from (select * from emp where addtime > '2020-01-06') as e left jion dept as d on e.empt_id = d.id