通過自定義CASE的SQL順序當訂購

Question

我試圖自定義ORDER BY子句，以便'其他公司'總是最後。我不確定這裏有什麼問題。這是我所有的代碼。 WHERE子句看起來可能是多餘的，但這是因爲參數被宏代碼替換，這個SQL字符串被上傳到不同的日期和狀態。別擔心。我之前已經完成了這項工作，以處理不同的情況，我訂購了一切，但沒有訂購兩列。輸出說ORDER BY子句中的'AmountOfClaims'不是一個有效的列。有人能幫我嗎？

SELECT 
    CASE 
     WHEN co.[CompanyName] != '' 
      THEN co.CompanyName 
      ELSE 'Unspecified Companies' 
    END AS CompanyName, 
    COUNT(co.[CompanyName]) AS [AmountOfClaims] 
FROM 
    (SELECT 
     CASE 
      WHEN [Claims].[CompanyName] IN (SELECT TOP 10 [Claims].[CompanyName] 
              FROM [Claims] 
              WHERE Claims.[HousingRequested] >= '2016-08-02' 
               AND Claims.[HousingRequested] <= '2016-08-16' 
               AND (Claims.[State] = NULL OR Claims.[State] >= CASE WHEN NULL IS NULL THEN ' ' ELSE 'ZZZZ' END) 
              GROUP BY [Claims].[CompanyName] 
              ORDER BY COUNT([Claims].[CompanyName]) DESC) 
       THEN [Claims].[CompanyName] 
       ELSE 'Other Companies' 
     END AS [CompanyName] 
    FROM 
     [Claims] 
    WHERE 
     Claims.[HousingRequested] >= '2016-08-02' 
     AND Claims.[HousingRequested] <= '2016-08-16' 
     AND (Claims.[State] = NULL OR Claims.[State] >= CASE WHEN NULL IS NULL THEN ' ' ELSE 'ZZZZ' END) 
    ) AS co 
GROUP BY 
    co.[CompanyName] 
ORDER BY 
    CASE 
     WHEN [CompanyName] = 'Other Companies' 
      THEN 9999 
      ELSE [AmountOfClaims] 
    END DESC 

Answer 1

您可以使用當前查詢作爲派生表或CTE，或者只是使用COUNT在ORDER BY：

SELECT 
    CASE WHEN co.[CompanyName] != '' THEN co.CompanyName ELSE 'Unspecified Companies' END AS CompanyName, 
    COUNT(co.[CompanyName]) AS [AmountOfClaims] 
FROM 
    (SELECT CASE WHEN [Claims].[CompanyName] IN 

      (SELECT TOP 10 [Claims].[CompanyName] 
      FROM [Claims] 
       WHERE Claims.[HousingRequested] >= '2016-08-02' 
       AND Claims.[HousingRequested] <= '2016-08-16' 
       AND (Claims.[State] = NULL OR Claims.[State] >= CASE WHEN NULL IS NULL THEN ' ' ELSE 'ZZZZ' END) 

      GROUP BY [Claims].[CompanyName] 
      ORDER BY COUNT([Claims].[CompanyName]) DESC) 

     THEN [Claims].[CompanyName] ELSE 'Other Companies' END AS [CompanyName] 

    FROM [Claims] 
     WHERE Claims.[HousingRequested] >= '2016-08-02' 
     AND Claims.[HousingRequested] <= '2016-08-16' 
     AND (Claims.[State] = NULL OR Claims.[State] >= CASE WHEN NULL IS NULL THEN ' ' ELSE 'ZZZZ' END) 
    ) AS co 

GROUP BY co.[CompanyName] 
ORDER BY CASE WHEN [CompanyName] = 'Other Companies' THEN 9999 ELSE COUNT(co.[CompanyName]) END DESC;