关于mysql:101mysql-left-join-一对多取右表最新一条记录

        SELECT            a.*,            e.userName as chatUser,            e.content as content,            e.chatTime as chatTime        FROM            gp_group AS a        LEFT JOIN (            SELECT b.* FROM chat_content b            LEFT JOIN (                SELECT MAX(c.id) AS id, c.groupUnid FROM chat_content c GROUP BY c.groupUnid            ) AS d ON d.groupUnid = b.groupUnid        WHERE b.id = d.id        ) AS e ON a.id = e.groupUnid        where 1=1        <if test="qo.status != null" >            and a.status = #{qo.status}        </if>        order by e.chatTime desc