部门人员统计（将下属部门人数汇总于一级部门）

表结构说明：

Dept表：

DeptID         DeptName                              ParentDeptID

1                   宜都市                                   0

2                   农业局                                   1

3                   纪委监察局                            1

4                  农业综合执法大队                  2 

5                  农业技术推广中心                  2 

6                  特产技术推广中心                  2

7                  党风室                                    3 

8                  干部室                                    3

 

Dept_User_Connection表：

CID         DeptID          UserID

1             2                    1

2             3                    2

3             4                    3

4             7                    4

5             8                    5

 

Users表：

UserID         UserName                             

1                  张三                                 

2                  李四                                   

3                  王五                    

4                  甲六                    

5                  丙丁           

                

需求说明：要求分组汇总 "宜都市" 所有下级部门人数总和。期望输出结果如下：

DeptID         DeptName      DeptUserCount

2                   农业局            2

3                   纪委监察局     3

 

解题思路：

1.查询 “农业局“ 及递归查询其所有下属部门；

with cte as
(
    select DeptID,ParentDeptID,DeptName,0 as lvl from Dept
    where DeptID=2
    union all
    select d.DeptID,d.ParentDeptID,d.DeptName,lvl+1 from cte c
    inner join Dept d on c.DeptID =d.ParentDeptID
)
select * from cte

go

 

2.创建标量函数，返回 ”农业局“ 关联所有的人员总数；

CREATE FUNCTION GetDeptUserCount
(
 @DeptID int
)
RETURNS int
AS
BEGIN
DECLARE @targetData VARCHAR(100);
 with cte as
 (
  select DeptID,ParentDeptID,DeptName,0 as lvl from Dept
  where DeptID=@DeptID
  union all
  select d.DeptID,d.ParentDeptID,d.DeptName,lvl+1 from cte c
  inner join Dept d on c.DeptID =d.ParentDeptID
 )
 select @targetData=COALESCE(COUNT(Connection.IN_USER_ID),0) from cte
 INNER JOIN Dept_User_Connection Connection ON Connection.IN_DEPT_ID=cte.IN_DEPT_ID
 INNER JOIN Users ON Connection.IN_USER_ID = Users.IN_USER_ID
 RETURN @targetData ;
END

go

 

3.分组查询 “宜都市“ 下级部门人员汇总数据。

 SELECT Dept.DeptID,Dept.DeptName,dbo.GetDeptUserCount(Dept.DeptID) FROM Dept
 WHERE ParentDeptID=1