mysql计算t_employee表领取奖金雇员的平均奖金数

第一步：先查询出每个部门的平均薪资，起别名t ，用作临时表(一会放入子查询)

-- 查询出每个部门的平均薪资，起别名t ，用作临时表(一会放入子查询)

SELECT

e.departmentid,AVG(e.salary) as avgsal

FROM

employee as e

GROUP BY

departmentid

结果图：

最终SQL代码：再为 t 表里的平均薪资查询出对应的薪资等级

-- 用查询出来的每个部门平均薪资表t，去匹配薪资等级表，找出每个部门的平均薪资是属于什么薪资等级

SELECT

t.departmentid,s.grade

FROM

(SELECT

e.departmentid,AVG(e.salary) as avgsal

FROM

employee as e

GROUP BY

e.departmentid) t

INNER JOIN

salgrade s

on

t.avgsal BETWEEN s.losal and s.hisal

ORDER BY

t.departmentid

最终查询后的结果图：

情景2、查询部门中所有人的薪资等级的平均等级

第一步：先查出每个部门里员工对应的薪资等级，起别名为 t ，用作临时表(一会用作子查询)

SELECT

e.*,s.grade

FROM

employee e

INNER JOIN

salgrade s

ON

e.salary BETWEEN s.losal and s.hisal

ORDER BY

departmentid

结果图：

最终SQL语句：再对 t 表里的每个部门员工的薪资等级求均值

SELECT

t.departmentid,AVG(t.grade) as avgra

FROM

(SELECT

e.*,s.grade

FROM

employee e

INNER JOIN

salgrade s

ON

e.salary BETWEEN s.losal and s.hisal

ORDER BY departmentid ) t

GROUP BY t.departmentid

建表，create table

修改表字段，alter table

删除表全部数据和表结果，drop table

MySQL对表的 *** 作还有对表内纪录的增删改查。

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