请教一句简单的SQL语句

[zhuwei1987]

表A 有字段A,B,C
表B 也是字段A,B,C
把两张表连接起来后.根据字段c对查询结果进行排列

[-狙击手-]

select * from ta
union all
select * from tb
order by c

[zhuwei1987]

为什么要加t?

[huangjh_love]

select * from(
select * from A union all
select * from B)a
where c='as'
order by c

[llj_8133]

select * from a union select * from b order by c

其实楼上的加不加T都代表“表”的名字。呵呵！

[dawugui]

[Quote=引用楼主 zhuwei1987 的帖子:]
表A 有字段A,B,C
表B 也是字段A,B,C
把两张表连接起来后.根据字段c对查询结果进行排列
[/Quote]

select * from A
union all
select * from B
order by c

[zhuwei1987]

CREATE PROCEDURE P_GetMapSearch
@district VarChar(30)
AS

select * from Message where district=@district
union all
select * from Message2 where district=@district
order by datetime
GO

出现错误205 包含UNION 运算符的SQL语句中的所有查询都必须在目标列表中具有相同数目的表达式??
这是什么原因

[areswang]

两表列数不同，字段个数不同。可以写成
select a,b from ta
union all
select a,b from tb