Oracle group by 和 OR 查詢優化

Question

SELECT BATCH_ID,
  BU_CODE,
  BU_TYPE,
  BATCH_TYPE,
  BATCH_GROUP_ID,
  STATUS,
  UPD_DTIME
FROM BATCH_T
WHERE (BU_CODE, BU_TYPE, BATCH_TYPE, UPD_DTIME) IN
  (SELECT BU_CODE,
    BU_TYPE,
    BATCH_TYPE,
    MAX(UPD_DTIME)
  FROM BATCH_T
  WHERE STATUS = 'CLOSED'
  GROUP BY BU_CODE,
    BU_TYPE,
    BATCH_TYPE
  )
OR UPD_DTIME >= SYSDATE - 5;

與上面的 Oracle Query 一樣，在沒有 OR 條件的情況下，它給出了快速響應，但是在 OR 條件下，它需要花費很多時間。 您能否幫助提高上述查詢的響應時間。

Answer 1

您需要最后關閉的記錄以及過去五天的所有內容。 使用窗口函數！

SELECT b.*
FROM (SELECT b.*,
             ROW_NUMBER() OVER (PARTITION BY BU_CODE, BU_TYPE, BATCH_TYPE, STATUS ORDER BY UPD_DTIME DESC) as seqnum
      FROM BATCH_T b
     ) b
WHERE UPD_DTIME >= SYSDATE - 5 OR
      (STATUS = 'CLOSED' AND seqnum = 1);

這應該比使用IN / EXISTS和聚合的任何方法都快。 寫起來也比較簡單。

Answer 2

以這樣的方式拆分查詢，其中應該有AND條件以獲得如下所示的性能增益。

 SELECT BATCH_ID,
  BU_CODE,
  BU_TYPE,
  BATCH_TYPE,
  BATCH_GROUP_ID,
  STATUS,
  UPD_DTIME
FROM BATCH_T
WHERE UPD_DTIME >= SYSDATE - 5

UNION ALL

SELECT BATCH_ID,
  BU_CODE,
  BU_TYPE,
  BATCH_TYPE,
  BATCH_GROUP_ID,
  STATUS,
  UPD_DTIME
FROM BATCH_T
WHERE (BU_CODE, BU_TYPE, BATCH_TYPE, UPD_DTIME) IN
  (SELECT BU_CODE,
    BU_TYPE,
    BATCH_TYPE,
    MAX(UPD_DTIME)
  FROM BATCH_T
  WHERE STATUS = 'CLOSED'
  GROUP BY BU_CODE,
    BU_TYPE,
    BATCH_TYPE
  ) AND NOT UPD_DTIME >= SYSDATE - 5;

Answer 3

您可以為 UPD_DTIME 創建索引