如何使PIVOT成為表/交叉表查詢？

Question

我已經執行了一條SELECT語句來獲取以下輸出：

MOVIE                           Critic Type  Average Rating
------------------------        ------------ --------------
30 Minutes or Less              Critic                 2.00
30 Minutes or Less              User                   4.20
A Lonely Place to Die           Critic                10.00
A Lonely Place to Die           User                   8.50
Taken                           Critic                 6.17
Taken                           User                   7.27
Taken 2                         Critic                 4.00
Taken 2                         User                   6.29

8 rows selected

這是SELECT語句：

SELECT MovieTitle AS "MOVIE", TBLCRITICCLASS.CRITICCLASSDESC AS "Critic Type", AVG(TBLREVIEW.REVIEWSTAR) AS "Average Rating"
FROM TBLMOVIE 
INNER JOIN TBLREVIEW ON TBLMOVIE.MOVIEID = TBLREVIEW.MOVIEID 
INNER JOIN TBLCRITIC ON TBLREVIEW.CRITICID = TBLCRITIC.CRITICID 
INNER JOIN TBLCRITICCLASS ON TBLCRITIC.CRITICCLASSID = TBLCRITICCLASS.CRITICCLASSID 
GROUP BY MovieTitle, TBLCRITICCLASS.CRITICCLASSDESC
ORDER BY Movietitle;

我想用PIVOT將此表轉換為此輸出，以得到具有評論者評分和用戶評分的輸出，因為它是其自己的類別：

MOVIE                           Critic Rating   User Rating
------------------------        -------------   -----------
30 Minutes or Less              2.00                   4.20
A Lonely Place to Die           10.00                  8.50
Taken                           6.17                   7.27
Taken 2                         4.00                   6.29

我嘗試這樣做：

SELECT * FROM
(
  SELECT MovieTitle AS "MOVIE", AVG(TBLREVIEW.REVIEWSTAR) AS "Critic Rating", AVG(TBLREVIEW.REVIEWSTAR) AS "User Rating"
  FROM TBLMOVIE 
  INNER JOIN TBLREVIEW ON TBLMOVIE.MOVIEID = TBLREVIEW.MOVIEID 
  INNER JOIN TBLCRITIC ON TBLREVIEW.CRITICID = TBLCRITIC.CRITICID 
  INNER JOIN TBLCRITICCLASS ON TBLCRITIC.CRITICCLASSID = TBLCRITICCLASS.CRITICCLASSID 
  GROUP BY MovieTitle, TBLCRITICCLASS.CRITICCLASSDESC
  ORDER BY Movietitle
)

PIVOT
(
  AVG(TBLREVIEW.REVIEWSTAR) AS "Critic Rating"
  FOR TBLREVIEW.REVIEWSTAR IN (TBLCRITICCLASS.CRITICCLASSDESC)

  AVG(TBLREVIEW.REVIEWSTAR) AS "User Rating"
  FOR TBLREVIEW.REVIEWSTAR IN (TBLCRITICCLASS.CRITICCLASSDESC)
)

我收到錯誤，這可能是由於我缺乏對子查詢的技巧，我想了解為什么我沒有得到我喜歡的輸出以及如何解決它。

編輯：

以下是相關的表：

File1（Pastebin）

File2（Pastebin）

Answer 1

您只是將樞紐聲明弄錯了。 您可以將查詢替換為下面的CTE，它應該可以工作。

SELECT * 
FROM (SELECT MovieTitle AS "MOVIE"
           , TBLCRITICCLASS.CRITICCLASSDESC AS      "Critic Type"
           , AVG(TBLREVIEW.REVIEWSTAR) AS "Average Rating"
      FROM TBLMOVIE 
      INNER JOIN TBLREVIEW 
        ON TBLMOVIE.MOVIEID = TBLREVIEW.MOVIEID 
      INNER JOIN TBLCRITIC 
        ON TBLREVIEW.CRITICID = TBLCRITIC.CRITICID 
      INNER JOIN TBLCRITICCLASS 
        ON TBLCRITIC.CRITICCLASSID = TBLCRITICCLASS.CRITICCLASSID 
      GROUP BY MovieTitle, TBLCRITICCLASS.CRITICCLASSDESC
      )
PIVOT (AVG("Average Rating") for "Critic Type" 
   in ('Critic' as "Critic Rating", 'User' as "User Rating")))
ORDER BY Movie

關於“為什么我沒有得到我的首選輸出”

您正在使用“臨界類型”，因為它具有兩個值（“臨界”和“用戶”），所以avg是有意義的； 但在您的示例中，每條記錄只有1個值，因此最小/最大也會起作用。

在數據透視圖中，您可以在數據透視的“輸入”部分中指定每一列，讓數據庫引擎根據“關鍵類型”列中的值確定如何組織數據。

因為必須指定每個值，所以如果沒有動態SQL，就無法擁有動態范圍。

注意：如果您希望使用與“ for”數據透視表字段中的值不同的名稱，則可以對數據透視表的“ IN”部分中的列進行別名命名。