SQL - 如何將結果從一個UNION結合

Question

UPDATE：

按照要求，這裏是「真正的」 SQL：

SELECT  p.ReferenceNumber, 
      p.Name, 
      '' as 'Size of Prize', 
      '' as 'Complexity', 
      pfc.ConfigurationValue as 'Strategic Fit' 
FROM  FormConfigurations AS fc INNER JOIN 
         ProjectForms AS pf ON pf.FormID = fc.FormID INNER JOIN 
         ProjectFormConfigurations AS pfc ON pfc.ProjectFormID = pf.ID AND pfc.FormConfigurationID = fc.ID INNER JOIN 
         Project AS p ON p.ID = pf.ProjectID 
WHERE  (fc.[Key] = 'Strategic Fit') 
GROUP BY p.ReferenceNumber, p.Name, pfc.ConfigurationValue, fc.[Key] 

UNION 

SELECT  p.ReferenceNumber, 
      p.Name, 
      '' as 'Size of Prize', 
      pfc.ConfigurationValue as 'Complexity', 
      '' 'Strategic Fit' 
      FROM   FormConfigurations AS fc INNER JOIN 
         ProjectForms AS pf ON pf.FormID = fc.FormID INNER JOIN 
         ProjectFormConfigurations AS pfc ON pfc.ProjectFormID = pf.ID AND pfc.FormConfigurationID = fc.ID INNER JOIN 
         Project AS p ON p.ID = pf.ProjectID 
WHERE  (fc.[Key] = 'Complexity') 
GROUP BY p.ReferenceNumber, p.Name, pfc.ConfigurationValue, fc.[Key] 

UNION 

SELECT  p.ReferenceNumber, 
      p.Name, 
    pfc.ConfigurationValue as 'Size of Prize', 
    '' as 'Complexity', 
    '' as 'Strategic Fit' 
    FROM   FormConfigurations AS fc INNER JOIN 
         ProjectForms AS pf ON pf.FormID = fc.FormID INNER JOIN 
         ProjectFormConfigurations AS pfc ON pfc.ProjectFormID = pf.ID AND pfc.FormConfigurationID = fc.ID INNER JOIN 
         Project AS p ON p.ID = pf.ProjectID 
WHERE  (fc.[Key] = 'Projected EBIT') 
GROUP BY p.ReferenceNumber, p.Name, pfc.ConfigurationValue, fc.[Key] 

我其中有一個鍵值列充當表在設計時不知道柱子的佔位符，這是另一塊大型軟件所必需的。我需要根據KeyValue列中的某些值獲取記錄;在這種情況下，讓我們調用所需的值Foo，Bar和Baz。每個檢索到的記錄必須具有全部三個值，否則它們不應該顯示。

下面是我用工會試圖查詢：

SELECT KeyValue as 'Foo', 
     '' as 'Bar', 
     '' as 'Baz' 
FROM  Table1 
WHERE  KeyValue = 'Foo' 
UNION 
SELECT '' as 'Foo', 
     KeyValue as 'Bar', 
     '' as 'Baz' 
FROM  Table1 
WHERE  KeyValue = 'Bar' 
SELECT '' as 'Foo', 
     '' as 'Bar', 
     KeyValue as 'Baz' 
FROM  Table1 
WHERE  KeyValue = 'Baz' 

不幸的是，什麼情況是，我有鋸齒的記錄，而不是所有的填充列的一個記錄。也就是說，不是我的獲取所需的記錄類似下面的：

Foo  Bar  Baz 
-  -  - 
-  -  - 
-  -  - 
-  -  - 
-  -  - 

我，而不是讓這些：

Foo  Bar  Baz 
-    
     -  
       - 
-    
     -  
       - 

什麼我需要做什麼來糾正我的查詢？

Answer 1

試試這個

select t1.KeyValue as 'Foo', t2.KeyValue as 'Bar', t3.KeyValue as 'Baz', 
from Table1 t1, Table1 t2, Table1 t3 
where t1.KeyValue = 'Foo' and t2.KeyValue = 'Bar' and t3.KeyValue = 'Baz' 

Answer 2

你需要使用什麼是選擇子查詢，而不是工會。聯合會將多個行源合併爲一個行源，但是您需要的是對於單個行，您需要從多個表中提取值。

例子：

select *, 
    (select KeyValue from table1 where somekey = outertable.somekey) as Foo 
from outertable where somerestrictions 

Answer 3

如果我理解你的需求，然後有很多方法，你提到的和簡單的方法之一是讓記錄：

SELECT KeyValue as 'Foo', 
     (SELECT KeyValue FROM zzz WHERE KeyValue = 'Bar') as 'Bar', 
     (SELECT KeyValue FROM zzz WHERE KeyValue = 'Baz') as 'Baz' 
FROM table1 
WHERE KeyValue = 'Foo' 

Answer 4

你沒有首先在第三個選擇查詢之前加上'union'。

如果你想消除重複行，你應該使用「UNION ALL」像如下：

SELECT KeyValue as 'Foo', 
 
     '' as 'Bar', 
 
     '' as 'Baz' 
 
FROM  Table1 
 
WHERE  KeyValue = 'Foo' 
 
UNION All 
 
SELECT '' as 'Foo', 
 
     KeyValue as 'Bar', 
 
     '' as 'Baz' 
 
FROM  Table1 
 
WHERE  KeyValue = 'Bar' 
 
UNION All 
 
SELECT '' as 'Foo', 
 
     '' as 'Bar', 
 
     KeyValue as 'Baz' 
 
FROM  Table1 
 
WHERE  KeyValue = 'Baz'

如果你不想以消除重複，那麼你應該使用只有 'UNION' 作爲像如下：

SELECT KeyValue as 'Foo', 
 
     '' as 'Bar', 
 
     '' as 'Baz' 
 
FROM  Table1 
 
WHERE  KeyValue = 'Foo' 
 
UNION 
 
SELECT '' as 'Foo', 
 
     KeyValue as 'Bar', 
 
     '' as 'Baz' 
 
FROM  Table1 
 
WHERE  KeyValue = 'Bar' 
 
UNION 
 
SELECT '' as 'Foo', 
 
     '' as 'Bar', 
 
     KeyValue as 'Baz' 
 
FROM  Table1 
 
WHERE  KeyValue = 'Baz'

我認爲這應該可以解決您的問題。 如果你願意，你可以看到'UNION'和'UNION ALL'之間的區別。

謝謝