查询各部门中高于部门平均工资的人员 人数及该部门的平均工资

dept表deptno，deptname

emp表empno，empname，salary，deptno

先通过查询得到平均工资视图，然后在联结查询平均工资表和员工表，Group by修饰count(*)，Group by要在where子句之后，order by子句之前。

select a.*,avgsalfrom emp as a,(select deptno,avg(salary) as avgsal from emp group by deptno) as bwhere a.deptno=b.deptno and a.salary>b.avgsalorder by a.deptno;

高于平均工资的人数

select a.deptno,avgsal,count(*) as numberfrom emp as a,(select deptno,avg(salary) as avgsal from emp group by deptno) as bwhere a.deptno=b.deptno and a.salary>b.avgsalgroup by a.deptnoorder by a.deptno;