Question

更新：

根据要求，这是'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]

我有一个具有KeyValue列的表，该列充当占位符，用于设计时未知的列，这是另一个大型软件所必需的。我需要根据KeyValue列中的某些值获取记录;在这种情况下，让我们调用所需的值Foo，Bar和Baz。检索到的每条记录必须包含所有三个值，否则它们根本不会显示。

以下是我尝试使用工会的查询：

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，发生的事情是我填充了所有列的锯齿状记录而不是一条记录。也就是说，而不是我得到如下所示的所需记录：

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

我得到了这些：

Foo     Bar     Baz
 -              
         -       
                 -
 -              
         -       
                 -

我需要做些什么来纠正我的查询？

Answer 1

试试这个

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

您需要使用的是选择子查询而不是联合。 union会将多个行源合并为1行源，但您需要的是，对于单行，您需要从多个表中获取值。

示例：

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

Answer 3

如果我理解了您的要求，那么有很多方法可以获得您提到的记录，其中一种简单的方法是：

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

首先，你没有把一个＆＃39;联盟＆＃39;在第三次选择查询之前

如果你想消除重复的行，你应该使用＆＃39; UNION ALL＆＃39;如下所示：

＆＃13;

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'

＆＃13;

如果你不想消除重复，那么你应该只使用＆＃39; UNION＆＃39;如下所示：

＆＃13;

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'

＆＃13;

我认为应该解决你的问题。如果你想要，你可以看到'UNION＆＃39;之间的区别。和＆＃39; UNION ALL＆＃39;。

谢谢

SQL - 如何组合UNION

4 个答案: