mysql count多个表的写法 多表联合查询的count用法

mysql count多个表的写法 多表联合查询的count用法.

SELECT (
SELECT count( * ) 
FROM `phpcms_content` 
) AS num, i.contentid
FROM `phpcms_content` t, `phpcms_c_news` i
WHERE t.contentid =3
AND t.contentid = i.contentid
LIMIT 0 , 30

 

 

num contentid

17	3