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5.查找所有员工的last_name和first_name以及对应部门编号dept_no.md 785 Bytes
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xuthus authored 2019-07-31 21:51 . add:1-20

查找所有员工的last_name和first_name以及对应部门编号dept_no

题目描述

查找所有员工的last_name和first_name以及对应部门编号dept_no,也包括展示没有分配具体部门的员工

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`));

题解

select last_name,first_name,dept_no from employees e left join dept_emp d on e.emp_no=d.emp_no

题解

left join的用法

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