sql 数据库 基础题 但是不会

Question

报错，求修正
表名称为Salary和Employee,括号里那个是工资

Answer 1

题主给的信息比较少，最好展示两个表的字段数据，以下是我根据现有情况猜测的思路，供参考：

1. Salary表中有Eid字段（猜测为外键员工ID）关联Employee获取部门；
2. 根据获取的部门分组聚合

   SELECT
    t2.Dept
   ,SUM(t1.Actual)    AS sum_actual
   ,AVG(t1.Actual)    AS avg_actual
   ,MAX(t1.Actual)    AS max_actual
   ,MIN(t1.Actual)    AS min_actual
   FROM
   (
    SELECT
        Eid
       ,Actual
    FROM Salary
    WHERE LauchDate BETWEEN '2017-03-01' AND '2017-03-31'
   ) t1
   LEFT OUTER JOIN
   (
    SELECT
        Eid
       ,Dept
    FROM Employee
   ) t2
   ON t1.Eid = t2.Eid
   GROUP BY t2.Dept
   ORDER BY avg_actual DESC
   ;