关键sql

分组后获取分组中对应的消息

主体思路，先分组，然后获取关键数据，进行级联或利用EXISTS关键字

SELECT * FROM (
SELECT B.*
FROM
  (SELECT ACCEPTNO,
          TASK_ID,
          MAX(TIME_MARKER) AS MTM
   FROM KK   WHERE TIME_MARKER > 5 AND FILD_COUNT < 5
   GROUP BY ACCEPTNO,
            TASK_ID) A
LEFT JOIN (SELECT * FROM KK WHERE TIME_MARKER > 5 AND FILD_COUNT < 5) B 
		   ON A.ACCEPTNO = B.ACCEPTNO
              AND A.TASK_ID = B.TASK_ID
              AND A.MTM = B.TIME_MARKER 
) T WHERE T.status = 'U';


SELECT *
FROM KK
WHERE TIME_MARKER > 5 AND FILD_COUNT < 5 
AND EXISTS (
    SELECT 1
    FROM (
        SELECT ACCEPTNO, TASK_ID, MAX(TIME_MARKER) AS MTM
        FROM KK
        WHERE TIME_MARKER > 5 AND FILD_COUNT < 5
        GROUP BY ACCEPTNO, TASK_ID
    ) T
    WHERE T.ACCEPTNO = KK.ACCEPTNO AND T.TASK_ID = KK.TASK_ID AND T.MTM = KK.TIME_MARKER 
) AND STATUS = 'U';