题目链接:

https://www.nowcoder.com/practice/c63c5b54d86e4c6d880e4834bfd70c3b?tpId=82&tqId=29755&tPage=1&rp=&ru=%2Fta%2Fsql&qru=%2Fta%2Fsql%2Fquestion-ranking

题目描述

查找各个部门当前(to_date='9999-01-01')领导当前薪水详情以及其对应部门编号dept_no
CREATE TABLE `dept_manager` (
`dept_no` char(4) NOT NULL,
`emp_no` int(11) NOT NULL,
`from_date` date NOT NULL,
`to_date` date NOT NULL,
PRIMARY KEY (`emp_no`,`dept_no`));
CREATE TABLE `salaries` (
`emp_no` int(11) NOT NULL,
`salary` int(11) NOT NULL,
`from_date` date NOT NULL,
`to_date` date NOT NULL,
PRIMARY KEY (`emp_no`,`from_date`));

 对象的既视感

select s.*,d.dept_no from salaries s,dept_manager d 
where s.to_date = "9999-01-01"
AND d.to_date = "9999-01-01"
AND s.emp_no = d.emp_no;