sql - 从外部选择语句的结果中选择

Question

如果我的方案有捷径，有人可以帮助我。

SELECT ProductName FROM Product where ProductId = 1012

此语句的结果是“DoubleDutch”

SELECT ColumnName FROM ProductMapping

此语句的结果是“ProductName”

SELECT (SELECT PM.ColumName FROM Product where ProductId = 1012) FROM ProductMapping PM

现在我只是期待结果是“DoubleDutch”，但结果仍然是“ProductName”

Answer 1

尝试这个：

DECLARE @Col VARCHAR(1000), @sql NVARCHAR(max)
SELECT @Col = ValueFromTableB from TableA
SELECT @sql = 'SELECT ' + @Col + ' FROM TableB
EXEC sp_executesql @sql

Answer 2

我认为这应该对你有用

DECLARE @Col VARCHAR(1000), @sql NVARCHAR(max)
Set @Col  = ''
SELECT @Col = @Col + ValueFromTableB + ' , ' from TableB
Set @Col = Left(@Col , (LEN(@Col) - 1))
SELECT @sql = 'SELECT TableAId , ' + @Col + ' FROM TableA'
EXEC sp_executesql @sql