select id,user_id, (select user_name from automessage_sys_user where user_id=a.user_id)userName, create_time,join_type FROM automessage_sys_user_record a DELETE FROM automessage_sys_user_record where id in (select id FROM( Select id,user_id,DATE_FORMAT(create_time,'%Y-%m-%d')create_time From automessage_sys_user_record Group By user_id,DATE_FORMAT(create_time,'%Y-%m-%d') Having Count(*)>1) k)