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SQL Server 2005新功能之TOP

  【IT168技术文档】

  TOP的语法在SQL  Server 2005中有新增加的东西了,可以支持update,delete,数学表达式等,举例如下:

  建立一个表如下:

Create table Mytable2 (au_id int, authors_name varchar(100)) Go insert into MyTable2 select 110,'Mathew Arnold' insert into MyTable2 select 140,'Keith Davis' insert into MyTable2 select 76,'David Taylor' insert into MyTable2 select 127,'Agatha Christy' insert into MyTable2 select 12,'Sidney Sheldon' insert into MyTable2 select 12,'Mcarthur' insert into MyTable2 select 76,'Alan Smiles' insert into MyTable2 select 100,'Kreisler' insert into MyTable2 select 88,'Jeff Watch' insert into MyTable2 select 99,'William Anderson' insert into MyTable2 select 99,'William Anderson' go

  使用UPDATE语句:

Update top (2) MyTable2 set authors_name = 'Mr.' + authors_name select * from MyTable2

  结果是:

au_id authors_name
110 Mr. Mathew Arnold
140 Mr. Keith Davis
76 David Taylor
127 Agatha Christy
12 Sidney Sheldon
12 Mcarthur
76 Alan Smiles
100 Kreisler
 88 Jeff Watch
99  William Anderson
99 William Anderson
              

  使用下面语句:

delete:delete top (1) MyTable2 where left(authors_name,2)= 'Mr' select * from MyTable2

  也可以设置表达式:

declare @n int set @n=3 select top (@n) * from MyTable2
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