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
- MySQL代码如何在 Windows环境下编译
- MYSQL出错代码列表
- mysql 5.0存储过程学习总结
- 迅速帮你解决 SQL Server 日志满问题
- SQL Server 2005 中能够使用 Try...Catch语句
- 启动SQL SERVER时自动执行存储过程
- 无法在SQL 2005系统数据库中执行的T-SQL语句(XML处理)
- MySQL关系数据库系统IF查询处理远程拒绝服务漏洞
- SQL Server 用户自定义的数据库修复
- 运行SQL Server的计算机之间移动数据库
- jsp从数据库取得数据作为下拉菜单选项的实现
- sql server2005 jdbc解决自动增长列统一处理问题纪实
- 使你的 SQL 语句完全优化
- 动态网页编程中优化数据库注意的十大原则
- SQL Server 2000数据库中如何重建索引
- mysql全文搜索索引的字段提高搜索效率
- 轻松八句话 教会你完全搞定MySQL数据库
- MySQL数据库中数据库移植中的乱码问题
- 分析数据库备份过程中九种可能出现的情况
- 对付ARP欺骗攻击16a.us病毒的解决方案
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: 107 ::
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
