[SQL] WHERE 條件合理性

利用 DMV 語法抓出有發生平行處理執行計劃時發現下述語法

SELECT
  S.ORDER_NO ,
  I.ODNO
FROM PMSETORDER AS S
  LEFT JOIN POITEM AS I ON S.ORDER_NO = I.ORDER_NO
WHERE S.ORDER_NO = @P1
  OR i.odno = @P2

從 DMV 抓出傳入的參數值是派工單號，然後更神奇的事情是，Odno 欄位是訂單編號，永遠不會成立的 WHERE 條件，Orz

修正 TSQL，把 Odno 條件拿掉

SELECT
  S.ORDER_NO ,
  I.ODNO
FROM PMSETORDER AS S
  LEFT JOIN POITEM AS I ON S.ORDER_NO = I.ORDER_NO
WHERE S.ORDER_NO = @P1

執行計畫比較