SELECT * FROM ( SELECT SUM(CASE WHEN f_enabled_mark = 0 THEN 1 ELSE 0 END) UnreadNum, f_send_user_id SendUserId, f_receive_user_id ReceiveUserId FROM base_im_content WHERE 1 = 1 AND f_receive_user_id = #{receiveUserId} GROUP BY f_send_user_id, f_receive_user_id ) t WHERE UnreadNum > 0 select f_send_user_id SendUserId, f_content DefaultMessage,f_content_type DefaultMessageType, f_send_time DefaultMessageTime from base_im_content WHERE 1 = 1 AND f_receive_user_id = #{receiveUserId} AND f_enabled_mark = 0 order by f_send_time desc UPDATE base_im_content SET f_enabled_mark = 1, f_receive_time = #{map.receiveTime} WHERE 1 = 1 AND f_enabled_mark = 0 AND f_send_user_id = #{map.sendUserId} AND f_receive_user_id = #{map.receiveUserId}