一.删除数据库中的重复数据, 只留一条

1 -- 删除数据库中的重复数据只留一条 2 DELETE  3 FROM 4     crm_member  5 WHERE 6     id IN ( 7     SELECT 8         a.id  9     FROM10         (11         SELECT12             id 13         FROM14             crm_member 15         WHERE16             phone IN ( SELECT phone FROM crm_member GROUP BY phone HAVING count( phone ) > 1 ) 17             AND id NOT IN ( SELECT min( id ) FROM crm_member GROUP BY phone HAVING count( phone ) > 1 ) 18         ) a 19     )