1. TOP 表达式
SQL Server 2000的TOP是个固定值，是不是觉得差强人意，现在改进了。
--前n名的订单
declare @n int
set @n = 10
select TOP(@n) * from Orders
2. 分页
不知大家过去用SQL Server 2000是如何分页的，大多都用到了临时表。SQL Server 2005就支持分页，性能也非常不错。
--按Freight从小到大排序，求20到30行的结果
select * from(select OrderId, Freight, ROW_NUMBER() OVER(order by Freight) as row from Orders) a
where row between 20 and 30
3. 排名
select * from(select OrderId, Freight, RANK() OVER(order by Freight) as rank from Orders) a
where rank between 20 and 30
4. try ... catch
SQL Server 2000没有异常，T-SQL必须逐行检查错误代码，对于习惯了try catch程序员，2005是不是更加亲切：
SET XACT_ABORT ON -- 打开 try功能
BEGIN TRY
begin tran
insert into Orders(CustomerId) values(-1)
commit tran
print 'commited'
END TRY
BEGIN CATCH
rollback
print 'rolled back'
END CATCH
5. 通用表达式CTE
通过表达式可以免除你过去创建临时表的麻烦。
例：结合通用表达式进行分页
WITH OrderFreight AS(
select OrderId, Freight, ROW_NUMBER() OVER(order by Freight) as row from Orders
)
select OrderId, Freight from OrderFreight where row between 10 and 20
特别之处：通过表达式还可以支持递归。
