如何在sql语句中实现变量?

[skydb]

我常要执行这样一类sql语句
select * from tableA where date='20003-6-30'
union all
select * from tableB where date='20003-6-30'
union all
select * from tableC where date='20003-6-30'
union all
select * from tableD where date='20003-6-30'

可不可以将其中的'2003-6-30'设成一个变量代替,这样在执行sql语名前我只需更改变量的值即可
谢谢

[caiyunxia]

declare @date datetime
select * from tableA where date=@date
union all
select * from tableB where date=@date
union all
select * from tableC where date=@date
union all
select * from tableD where date=@date

[pengdali]

declare @a datetime
set @a='2003-6-30'
select * from tableA where date=@a
union all
select * from tableB where date=@a
union all
select * from tableC where date=@a
union all
select * from tableD where date=@a

[skydb]

结了分,发现问题:

DECLARE @theDate datetime
SELECT @theDate = '20003-6-30'

select * from orderin where 入库日期 = @theDate

执行后提示:
服务器: 消息 241，级别 16，状态 1，行 2
从字符串转换为 datetime 时发生语法错误。

所以不得不再发贴请教了

[xueqs]

这好象只能在存储过程重用吧