今天写了个SQL语句

select * from (

select ... from A? union ?select ...from B order by B.xx

) as Tmp

SQL查询分析器中老是报错：The ORDER BY clause is invalid in views, inline functions, derived tables, and subqueries, unless TOP is also specified.

而单独执行select ... from A? union ?select ...from B order by B.xx语句时是可以的。

后来分析原因如下：

sql中建view是不能用order by字句的，即：

如果把该查询语句建成视图? create view v_test? as? select * from sysobjects order by name? 会提示出错:The ORDER BY clause is invalid in views, inline functions, derived tables, and subqueries, unless TOP is also specified.

而在嵌套查询中，系统会自动为select ... from A? union ?select ...from B order by B.xx语句建一个view，里面有order by字句，当然会报错了，去掉order by后，运行成功！