mysql中删除重复记录

原文链接：http://blog.csdn.net/dsiori/article/details/52806709

DELETE FROM `user` WHERE id NOT IN(SELECT * FROM(SELECT id FROM `user` GROUP BY username)AS b)  

DELETE FROM rf_data_tuchong_tag WHERE tag_id IN ( SELECT tag_id FROM ( SELECT tag_id, min( id ) id, count(*) num FROM rf_data_tuchong_tag GROUP BY tag_id HAVING num > 1 ) a ) AND id NOT IN ( SELECT id FROM ( SELECT tag_id, min( id ) id, count(*) num FROM rf_data_tuchong_tag GROUP BY tag_id HAVING num > 1 ) b )

DELETE 
FROM
	love_tc_post 
WHERE
	post_id IN (
	SELECT
		post_id 
	FROM
		( SELECT post_id, min( id ) id, count(*) num FROM love_tc_post GROUP BY post_id HAVING num > 1 ) a 
	) 
	AND id NOT IN (
	SELECT
		id 
	FROM
	( SELECT post_id, min( id ) id, count(*) num FROM love_tc_post GROUP BY post_id HAVING num > 1 ) b 
	)