浅谈MySQL数据库中如何解决分组统计的问题_MySQL
内容导读
互联网集市收集整理的这篇技术教程文章主要介绍了浅谈MySQL数据库中如何解决分组统计的问题_MySQL,小编现在分享给大家,供广大互联网技能从业者学习和参考。文章包含1245字,纯文字阅读大概需要2分钟。
内容图文
首先准备四张表A、B、C、D,--------------------------------
A | B | C | D
a b | a c | a d | d e
1 1 | 1 1 | 1 A | A 1
2 2 | 1 3 | 2 B | B 2
3 4 | 1 4 | 3 C | C 3
4 6 | 2 1 | 4 D | D 4
--------------------------------
下面我们需要用一条sql语句将A表所有的列,B表对与A表a字段相关联的列求count,通过C表,将D表与A表关联起来,得到的结果如下:
1 1 3 1
2 2 1 2
3 4 0 3
4 6 0 4
Mysql语句解决:
select A.a,A.b,IFNULL(c,0) as c,D.a
from (select 1 as a,2 as b union all
select 2 as a,2 as b union all
select 3 as a,4 as b union all
select 4 as a,6 as b) as A
left outer join
(select a,count(a) as c from(
select 1 as a,3 as c union all
select 1 as a,3 as c union all
select 1 as a,3 as c union all
select 2 as a,3 as c ) B group by a) as B
on A.a=B.a
join
(select 1 as a,'A' as d union all
select 2 as a,'B' as d union all
select 3 as a,'C' as d union all
select 4 as a,'D' as d ) as C
on A.a=C.a
join(select 1 as a,'A' as d union all
select 2 as a,'B' as d union all
select 3 as a,'C' as d union all
select 4 as a,'D' as d ) as D
on D.d=C.d
内容总结
以上是互联网集市为您收集整理的浅谈MySQL数据库中如何解决分组统计的问题_MySQL全部内容,希望文章能够帮你解决浅谈MySQL数据库中如何解决分组统计的问题_MySQL所遇到的程序开发问题。 如果觉得互联网集市技术教程内容还不错,欢迎将互联网集市网站推荐给程序员好友。
内容备注
版权声明:本文内容由互联网用户自发贡献,该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务,不拥有所有权,不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容, 请发送邮件至 gblab@vip.qq.com 举报,一经查实,本站将立刻删除。
内容手机端
扫描二维码推送至手机访问。