Sql 如何从另一个表动态化列别名

我有下面的查询，我正在寻找从另一个表中动态显示列名标签的方法。 在表#Tmp2中，Dim1根据Dim1.Num变化，例如我可以 对于

Dim1.Num=1=>Dim1=BusinessUnit

在其他cas中，我可以拥有

Dim1.Num=1=>Dim1=Department

SELECT Dim1.Dim1 ,Dim1.ValueDim1  ,
       Dim2.Dim2 ,Dim2.ValueDim2  ,
       #Tmp1.Amount

INTO   #Tmp3

FROM   #Tmp1

INNER JOIN #Tmp2 as Dim1 on Dim1.id = #Tmp1.id And Dim1.Num=1
INNER JOIN #Tmp2 as Dim2 on Dim1.id = #Tmp1.id And Dim2.Num=2

结果是：

Dim1            ValueDim1  Dim2         ValueDim2  Amount
BusinessUnit    002        Department   027        1000

但是我想要这个结果

BusinessUnit    ValueDim1  Department   ValueDim2  Amount
BusinessUnit    002        Department   027        1000

也就是说，根据

#Tmp2.Num的值，列的适用名称可以更改

我可能是这样的

SELECT Dim1.Dim1 AS (select Dim from #Tmp2 where #Tmp2.Num = 1)

您可以使用动态SQL：

DECLARE @ColName VARCHAR(20) = (select Dim from #Tmp2 where #Tmp2.Num = 1)

EXEC('SELECT Dim1.Dim1 ['+@ColName+'] ,Dim1.ValueDim1  ,
       Dim2.Dim2 ,Dim2.ValueDim2  ,
       #Tmp1.Amount

INTO   #Tmp3

FROM   #Tmp1

INNER JOIN #Tmp2 as Dim1 on Dim1.id = #Tmp1.id And Dim1.Num=1
INNER JOIN #Tmp2 as Dim2 on Dim1.id = #Tmp1.id And Dim2.Num=2')

这样做的局限性（以及您的一般问题）是，如果您的
#Tmp2
有两条记录具有相同的
Num
，那么查询将抛出一个
子查询，返回多个值。解决此问题的唯一方法是更改@ColName查询，使其仅返回单个值：

DECLARE @ColName VARCHAR(20) = (select TOP 1 Dim from #Tmp2 where #Tmp2.Num = 1)

更新：

如果获取列名的查询可能返回0条记录，请按如下方式修改查询：

DECLARE @ColName VARCHAR(20) = (
    select Dim from #Tmp2 where #Tmp2.Num = 1 
    UNION 
    SELECT 'DefaultValue' WHERE NOT EXISTS (select Dim from #Tmp2 where #Tmp2.Num = 1)
    )

但是，如果查询返回一条记录，但要用作列名的列中的值为null，则按如下方式修改查询：

DECLARE @ColName VARCHAR(20) = (select ISNULL(Dim,'DefaultValue') from #Tmp2 where #Tmp2.Num = 1)

看起来我有一个问题，有时我有@ColName null，所以我必须做一些类似的事情：Dim7.Dim7.FinalValue，当Dim7.FinalValue=''然后Dim7 ELSE['+@Dim7+']结束