如何加快我從另一列中的值創建新列的查詢？

Question

我不完全確定所要求的措辭，但我正在嘗試爲報告創建查詢，並且我想要創建的每個列的所有值都在當前的單個列中。這是我目前的查詢：

SELECT [SubjectID] 
    ,(SELECT [DataValue] 
     FROM [SummarySubjectDataValueAll] 
     WHERE [LibraryEventID] IN (
       SELECT [LibraryEventID] 
       FROM [LibraryEvent] 
       WHERE [Name] LIKE '%First Name%') 
    ) as FirstName 
    ,(SELECT [DataValue] 
     FROM [SummarySubjectDataValueAll] 
     WHERE [LibraryEventID] IN 
        (SELECT [LibraryEventID] 
         FROM [LibraryEvent] 
         WHERE [Name] LIKE '%Last Name%')) as LastName 
    ,(SELECT [DataValue] 
     FROM [SummarySubjectDataValueAll] 
     WHERE [LibraryEventID] IN (
       SELECT [LibraryEventID] 
       FROM [LibraryEvent] 
       WHERE [Name] LIKE 'Primary Phone')) as Phone 
    ,(SELECT [DataValue] 
     FROM [SummarySubjectDataValueAll] 
     WHERE [LibraryEventID] IN (
      SELECT [LibraryEventID] 
      FROM LibraryEvent] 
      WHERE [Name] = 'Secondary Phone')) as Phone2 
     ,(SELECT [DataValue] 
     FROM [SummarySubjectDataValueAll] 
     WHERE [LibraryEventID] IN (
       SELECT [LibraryEventID] 
       FROM [LibraryEvent] 
       WHERE [Name] = 'Next of Kin Phone')) as KinPhone 
    FROM [SummarySubjectDataValueAll] 
    WHERE DataValue = @Phone 

（單獨，他們查詢拉什麼我需要和非常快）。試圖拉動信息的時間超過10分鐘或更長時間，我知道這是因爲我再次將它運行在同一張桌子上6次。我不記得如何以更有效的方式做到這一點。有人可以協助嗎？本報告正在做什麼的一些背景：它本質上是一個反向電話目錄。我需要根據他們的電話號碼提取這個人的信息，這個電話號碼可以是上述三種類型中的任何一種（小學，中學或最近的親屬）。

預先感謝您

Answer 1

您可以通過使用條件與聚集只需CASE EXPRESSION避免這一切的嵌套的選擇：

SELECT t.subjectID, 
     MAX(CASE WHEN t.name LIKE '%First Name%' THEN t.DataValue END) as FirstName, 
     MAX(CASE WHEN t.name LIKE '%Last Name%' THEN t.DataValue END) as LastName, 
     MAX(CASE WHEN t.name = 'Primary Phone' THEN t.DataValue END) as Phone, 
     MAX(CASE WHEN t.name = 'Secondary Phone' THEN t.DataValue END) as Phone2, 
     MAX(CASE WHEN t.name = 'Next of Kin Phone' THEN t.DataValue END) as KinPhone 
FROM SummarySubjectDataValueAll t 
JOIN LibraryEvent s 
ON(t.LibraryEventID = s.LibraryEventID) 
GROUP BY t.subjectID