SELECT * FROM blog_user_relation a WHERE (a.account_instance_id,a.follow_account_instance_id)
IN (SELECT account_instance_id,follow_account_instance_id FROM blog_user_relation GROUP BY account_instance_id, follow_account_instance_id HAVING
COUNT(*) > 1)
/*創(chuàng)建個(gè)臨時(shí)表*/
CREATE TABLE blog_user_relation_temp AS
(
SELECT * FROM blog_user_relation a WHERE
(a.account_instance_id,a.follow_account_instance_id)
IN ( SELECT account_instance_id,follow_account_instance_id FROM blog_user_relation GROUP BY account_instance_id, follow_account_instance_id HAVING COUNT(*) > 1)
AND
relation_id
NOT IN (SELECT MIN(relation_id) FROM blog_user_relation GROUP BY account_instance_id, follow_account_instance_id HAVING COUNT(*)>1));
/*刪除數(shù)據(jù)*/
DELETE FROM `blog_user_relation` WHERE relation_id IN (SELECT relation_id FROM blog_user_relation_temp);
/*刪除臨時(shí)表*/
DROP TABLE blog_user_relation_temp;