MySQL --复合查询

1.基本查询回顾

查询工资高于500或岗位为MANAGER的雇员，同时还要满足他们的姓名首字母为大写的J

select * from emp where (sal>500 or job='MANAGER') and ename like 'J%';

按照部门号升序而雇员的工资降序排序

select * from emp order by deptno, sal desc;

使用年薪进行降序排序

select ename, sal*12+ifnull(comm,0) as '年薪' from emp order by 年薪 desc;

显示工资最高的员工的名字和工作岗位

select ename, job from emp where sal = (select max(sal) from emp);

显示工资高于平均工资的员工信息

select ename, sal from emp where sal>(select avg(sal) from emp);

显示每个部门的平均工资和最高工资

select deptno, format(avg(sal), 2) , max(sal) from emp group by deptno;

显示平均工资低于2000的部门号和它的平均工资

select deptno, avg(sal) as avg_sal from emp group by deptno having avg_sal<2000;