题目地址:

https://www.nowcoder.com/practice/6d35b1cd593545ab985a68cd86f28671?tpId=82&tqId=29756&tPage=1&rp=&ru=%2Fta%2Fsql&qru=%2Fta%2Fsql%2Fquestion-ranking

题目描述

查找所有已经分配部门的员工的last_name和first_name以及dept_no
CREATE TABLE `dept_emp` (
`emp_no` int(11) NOT NULL,
`dept_no` char(4) NOT NULL,
`from_date` date NOT NULL,
`to_date` date NOT NULL,
PRIMARY KEY (`emp_no`,`dept_no`));
CREATE TABLE `employees` (
`emp_no` int(11) NOT NULL,
`birth_date` date NOT NULL,
`first_name` varchar(14) NOT NULL,
`last_name` varchar(16) NOT NULL,
`gender` char(1) NOT NULL,
`hire_date` date NOT NULL,
PRIMARY KEY (`emp_no`));

通过emp_no关键字连接就好了

select e.last_name,e.first_name,d.dept_no from employees e,dept_emp d
where e.emp_no = d.emp_no
;