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SQL统计部门人数,人数为0的部门也要显示出来

时间:2019-05-30 20:28:32      阅读:215      评论:0      收藏:0      [点我收藏+]

 

相同点:它们都以一张部门表(或类别表),其它表都有部门编号DepartmentID(类别编号)

案例一:一张表

 select c.DepartmentID,c.DepartmentName, t.Num AS ‘人员数量‘ from T_Department as c 
left join (select DepartmentID,COUNT(*) AS Num from T_User   group by DepartmentID) as t on c.DepartmentID= t.DepartmentID

核心思想就是: 拆分

1将人员表按部门编号统计数量: ( select DepartmentID,COUNT(*) AS Num from T_User   group by CompanyID) 得到t: 部门编号、部门人员数量;

2将 部门表与 t ,根据部门编号联表左连接,得到 :部门名称、部门人员数量

 

案例二:多张表

统计提交的 调查人员、设备、规范、数据来源规范 表的数量

期初我是这样做的:

select c.CompanyName, t.Num from T_Company as c left join (select CompanyID,COUNT(*) AS Num from T_Standard as s where s.HasSubmitted=1 group by CompanyID) as t on c.CompanyID= t.CompanyID order by c.CompanyID
select c.CompanyName, t.Num from T_Company as c left join (select CompanyID,COUNT(*) AS Num from T_Investigator as s where s.HasSubmitted=1 group by CompanyID) as t on c.CompanyID= t.CompanyID order by c.CompanyID
select c.CompanyName, t.Num from T_Company as c left join (select CompanyID,COUNT(*) AS Num from T_Machine as s where s.HasSubmitted=1 group by CompanyID) as t on c.CompanyID= t.CompanyID order by c.CompanyID
select c.CompanyName, t.Num from T_Company as c left join (select CompanyID,COUNT(*) AS Num from T_DataSource as s where s.HasSubmitted=1 group by CompanyID) as t on c.CompanyID= t.CompanyID order by c.CompanyID

然和一个一个复制到一张Excel。

后来我是这样的:
select c.CompanyID,c.CompanyName, t1.Num AS ‘调查人员数量‘,t2.Num AS ‘设备数量‘,t.Num AS ‘规范数量‘,t3.Num AS ‘数据来源规范数量‘ from T_Company as c
left join (select CompanyID,COUNT(*) AS Num from T_Standard as s where s.HasSubmitted=1 group by CompanyID) as t on c.CompanyID= t.CompanyID
left join (select CompanyID,COUNT(*) AS Num from T_Investigator as s where s.HasSubmitted=1 group by CompanyID) as t1 on c.CompanyID= t1.CompanyID
left join (select CompanyID,COUNT(*) AS Num from T_Machine as s where s.HasSubmitted=1 group by CompanyID) as t2 on c.CompanyID= t2.CompanyID
left join (select CompanyID,COUNT(*) AS Num from T_DataSource as s where s.HasSubmitted=1 group by CompanyID) as t3 on c.CompanyID= t3.CompanyID
order by c.CompanyID

最后赋值粘贴到Excel,在Excel搞个合计:

技术分享图片

 

SQL统计部门人数,人数为0的部门也要显示出来

原文:https://www.cnblogs.com/hao-1234-1234/p/10951418.html

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