sql server案例

Question

我想根据一个名为'type‘的参数从不同的表中进行选择。我可以使用'CASE‘来选择from表吗？

我能用这样的东西吗？

select 
a as abc
b as xyz
from ( CASE when @type = 1 then tblSales
            when @type = 2 then tblTransfer
       end
)

Answer 1

这就是你要找的吗？

select
    a as abc,
    b as xyz
from 
    tblSales
WHERE
    @type = 1
UNION
select
    a as abc,
    b as xyz
FROM 
    tblTransfer
WHERE
    @type = 2

Answer 2

我可能会这样做：

SELECT a AS abc, b AS xyz FROM tblSales WHERE @type=1
UNION ALL
SELECT a AS abc, b AS xyz FROM tblTransfer WHERE @type=2

Answer 3

Declare @Sql nvarchar(4000)
Declare @type   int
SET @type = 1

SET @Sql = ''

set @Sql = @Sql + '
    select * FROM '
IF @type = 1
BEGIN
    set @Sql = @Sql + '[tblSales]'
END
ELSE
BEGIN
    set @Sql = @Sql + 'tblTransfer'
END

print @sql
exec (@Sql)