一条语句中查询数据库表中state字段为不同情况下的记录数

一条语句中查询数据库表中state字段为不同情况下的记录数

SELECT
Count_1=(SELECT Count(*) FROM Table1 WHERE state= 1),
Count_2=(SELECT Count(*) FROM Table1 WHERE state= 2),

Count_3=(SELECT Count(*) FROM Table1)

 

相同的方法

从多个表里获得count值

SELECT
(SELECT COUNT(DISTINCT id) FROM member) AS members,
(SELECT COUNT(DISTINCT id) FROM thread) AS threads,
(SELECT COUNT(DISTINCT id) FROM post) AS posts

不要用

SELECT COUNT(DISTINCT member.id), COUNT(DISTINCT thread.id), COUNT(DISTINCT post.id) FROM member, thread, post;

这种情况下，如果某个count为零，其他都为零

 

好久没写东西了，随便写点^_^