2022-01-17 阅读量: 261
-- 查询manager的姓名、所属部门名称和入职日期：ename,dname,job,hiredate(内连接/笛卡尔积连接)
select ename,dname,job,hiredate
from emp
inner join dept
on emp.deptno=dept.deptno
where job='manager';
select ename,dname,job,hiredate
from emp,dept
where emp.deptno=dept.deptno and job='manager';
-- 查询所有员工姓名及其直属领导姓名（自连接：通过别名，将同一张表视为多张表）
select emp.ename as 员工姓名,leader.ename as 直属领导姓名
from emp
left join emp as leader
on emp.mgr=leader.empno;
