重复数据查询（sql）

需求：查询user_log表中uid值重复的数据

SELECT
	uid,
	count( * ) AS count 
FROM
	user_log 
GROUP BY
	uid 
HAVING
	( count ) > 1

需求：查询重复数据的总数

SELECT
	sum( count ) 
FROM
	( SELECT count( * ) AS count FROM user_log GROUP BY uid HAVING count( * ) > 1 ) a