繁體中文当前位置: 首页 > 图文教程 > 数据库 > MYSQL > 浅谈MySQL数据库中如何解决分组统计的问题
- MYSQL
- Windows下对MySQL安装的故障诊断与排除
- 解析：校对确定 较为复杂的一些特殊情况
- 解析：轻松掌握 字符串文字字符集和校对
- 教你快速了解公共MySQL的数据库服务器层
- MYSQL和ORACLE的一些操作区别
- MySQL的6种日志详解
- 巧用MySQL InnoDB引擎锁机制解决死锁问题
- 怎样正确的解决 MySQL 中文模糊检索问题
- 教你轻松掌握如何保护MySQL中的重要数据
- 细化解析：怎样把你的MySQL完全中文化
- 带你轻松接触 MySQL中损坏的MyISAM表
- 解析：以mysql_开始的未定义引用错误
- 不同操作系统下的mysql数据库同步
- MySQL优化之数据表的处理
- 安装MySQL错误归档处理
- MySQL分页优化解析
- 数据库新手入门之MYSQL出错代码列表
- 经验之谈：MySQL与ASP.NET配合更强大
- MySQL数据库的其它安全问题
- RHEL下架设MYSQL集群
MYSQL 中的 浅谈MySQL数据库中如何解决分组统计的问题
出处:互联网 整理: 软晨网（RuanChen.com） 发布: 2009-09-30 浏览: 103 ::
收藏到网摘: n/a
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 |
评论 (0) All
