Sql server 2008 sql server案例

我想根据名为“type”的参数从不同的表中进行选择。我可以使用“CASE”从表中选择

我可以用这样的东西吗

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

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

如果您想这样做，您可以尝试使用union（下面的示例），也可以使用简单的“if”语句

这里不能使用case语句，因为case返回的是单个值，而不是表（这是“from”所期望的）

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

这就是我将要做的——打败我！如果您发布代码、XML或数据示例，请在文本编辑器中突出显示这些行，并单击编辑器工具栏上的“代码示例”按钮（
{}
），以很好地格式化和语法突出显示它！谢谢；将来会这样做的！
create table #tblsales
(
    a varchar(1),
    b varchar(1)
)

create table #tblTransfer
(
    a varchar(1),
    b varchar(1)
)

insert into #tblSales(a,b) values ('s','1')
insert into #tblSales(a,b) values ('s','2')

insert into #tblTransfer(a,b) values ('t','1')
insert into #tblTransfer(a,b) values ('t','2')

declare @type int
set @type=1

select a as abc, b as xyz
from
    (
    select a,b,thetype
    from
        (select a,b, 1 as thetype from #tblsales) sales
        union
        (select a,b, 2 as theType from #tblTransfer)
    ) joined
where theType=@type

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