使用CASE WHERE動態設置TSQL查詢的結果

SELECT MyTable.Name, 
     (
      SELECT CASE WHEN ISNULL(SUM(TotalDays), 0) <= 0 THEN 0 
         ELSE SUM(TotalDays) 
      END AS Total 
      FROM Application AS Applications 
      WHERE (ID = MyTable.id) 
     ) - MIN(Assignments) AS Excesses 
FROM MyTable

上述TSQL語句是主查詢中的子查詢。當我運行它時，如果TotalDays爲NULL或< = 0，則Total設置爲0（零）。使用CASE WHERE動態設置TSQL查詢的結果

我想在這裏做什麼是對整個查詢（超支）的結果設置爲0。我想（超支）這是總的結果 - 最小（分配）設置爲0如果它的NULL或< = 0。

我想要CASE當適用於整個查詢，但我正在努力做到正確。

來源

2010-05-27 StackTrace

你的問題不明確（至少對我來說）可以請您給所涉及的表的結構，什麼是你需要得到你quesy – 2010-05-27 13:03:36

我重新格式化DAT根據你的括號，這是正確的嗎？ – Blorgbeard 2010-05-27 13:07:02

是的編輯的格式非常正確 – StackTrace 2010-05-27 13:13:54

SELECT 
    MyTable.Name, 
    CASE WHEN 
    0 < (SELECT SUM(TotalDays) FROM Application WHERE ID = MyTable.id) - MIN(Assignments) 
    THEN 
    (SELECT SUM(TotalDays) FROM Application WHERE ID = MyTable.id) - MIN(Assignments) 
    ELSE 
    0 
    END AS [Excesses] 
FROM 
    MyTable

注：MS SQL Server將不exexute兩個相關子查詢independantly，它將INFACT認識到，它們是相同的和重複使用的結果。

備選：

SELECT 
    MyTable.Name, 
    CASE WHEN 
    0 < SUM([application].TotalDays) - MIN([MyTable].Assignments) 
    THEN 
    SUM([application].TotalDays) - MIN([MyTable].Assignments) 
    ELSE 
    0 -- If either aggregate is NULL, 0 will still be returned 
    END AS [Excesses] 
FROM 
    MyTable 
LEFT JOIN 
    Application 
    ON [application].ID = [MyTable].id

來源

2010-05-27 13:44:46 MatBailie

謝謝。我採取了第一個選擇，它的確做到了正確的工作。 – StackTrace 2010-05-27 14:17:14

SELECT MyTable.Name, CASE WHEN ISNULL(SUM(TotalDays), 0) <= 0 THEN 0 ELSE SUM(TotalDays) END AS Total 
FROM Application AS Applications 
JOIN MyTable 
ON  Applications.id = mytable.id 
GROUP BY 
     MyTable.id, MyTable.name 
HAVING CASE WHEN ISNULL(SUM(TotalDays), 0) <= 0 THEN 0 ELSE SUM(TotalDays) END > 0

來源

2010-05-27 13:02:07 Quassnoi

使用CASE WHERE動態設置TSQL查詢的結果

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