查詢SQL服務器時SQL語法錯誤

Question

希望有人可以幫我清理一個查詢，我遇到了問題。在我從每組修訂版中返回最新修訂版後，我試圖將結果分成一半。

我可以用這一半的結果分爲：

SELECT * 
     FROM 
     (
     SELECT *, ntile(2) over(order by ID) as tile_nr 
     FROM dbTable 
    ) x 
    WHERE x.tile_nr = 1 

我可以從修訂的羣體獲得的最新修訂本：

SELECT b1.* 
     FROM dbTable b1 
     INNER JOIN 
      (
       SELECT ID, max(revision) as revision 
       FROM dbTable 
       GROUP BY ID 
      ) as b2 
      ON b1.ID = b2.ID and 
      (
       b1.revision = b2.revision or b2.revision is null 
      ) 

但是，當我嘗試將這些查詢合併成一個這樣的：

SELECT * 
    FROM 
    (
     SELECT *, ntile(2) over(order by ID) as tile_nr 
     FROM 
     (
      SELECT b1.* 
      FROM dbTable b1 
      INNER JOIN 
       (
        SELECT ID, max(revision) as revision 
        FROM dbTable 
        GROUP BY ID 
      ) as b2 
      ON b1.ID = b2.ID and 
       (
        b1.revision = b2.revision or b2.revision is null 
      ) 
     ) 
    ) x 
    WHERE x.tile_nr = 1 

我得到一個 「錯誤snytax附近 '）'」 的錯誤。它似乎不喜歡最後一個括號。

任何幫助將不勝感激。

Answer 1

這是那些情況下縮進在調試有用之一：

SELECT * 
FROM 
(
    SELECT *, ntile(2) over(order by ID) as tile_nr 
    FROM 
    (
     SELECT bt.* 
     FROM dbTable b1 
     INNER JOIN 
     (
      SELECT ID, max(revision) as revision 
      FROM dbTable 
      GROUP BY ID as b2 
      ON b1.ID = b2.revision or b2.revision is null 
     ) 
    ) 
) x 
WHERE x.tle_nr = 1 

具體，你的內心SELECT包括ON子句並不在該範圍內纔有意義。你需要生成子查詢結果集，別名一個名稱，然後在你的加入condtions使用別名名稱：

SELECT bt.* 
    FROM dbTable b1 
    INNER JOIN 
    (
     SELECT ID, max(revision) as revision 
     FROM dbTable 
     GROUP BY ID 
    ) as b2 
    ON b1.ID = b2.revision or b2.revision is null 

跟進編輯：

它看起來像走樣子查詢，你NTILE（） SELECT解決了這個問題：

SELECT *, ntile(2) over(order by ID) as tile_nr 
    FROM 
    (subquery) as subQ