神奇魔法之求分组后的每一组的时间最大值行

SELECT * FROM(SELECT * FROM    (SELECT msg.*,new2.id as mem_id FROM xchl_chat_msg as msg,(SELECT  DISTINCT(news.id) FROM (SELECT source_id as id,create_time FROM xchl_msg   WHERE (( (source_id = 100600065 OR member_id = 100600065) ) AND type = 9) 
                UNION
SELECT member_id as id,create_time FROM xchl_msg   WHERE (( (source_id = 100600065 OR member_id = 100600065) ) AND type = 9) ORDER BY create_time DESC) as news LEFT JOIN xchl_member            as member on member.id=news.id     WHERE news.id!=100600065) AS new2  WHERE msg.member_id=new2.id and msg.to_member_id=100600065 or msg.member_id=100600065  and msg.to_member_id= new2.id    )
 AS a WHERE a.mem_id HAVING 1 ORDER BY a.create_time DESC) as b GROUP BY b.mem_id;

使用

select * from (select * table where 要分组的字段 having 1 order by create_time desc) as alia group by alia. 要分组的字段;后