Sql分页语句
今天闲来无事,测试了一下用Sql分页语句,从网上找了一些数据,总结Sql分页分为5种:
--写法1,not in/top select top 50 * from pagetest where id not in (select top 9900 id from pagetest order by id) order by id --写法2,not exists select top 50 * from pagetest where not exists (select 1 from (select top 9900 id from pagetest order by id)a where a.id=pagetest.id) order by id --写法3,max/top select top 50 * from pagetest where id>(select max(id) from (select top 9900 id from pagetest order by id)a) order by id --写法4,row_number() select top 50 * from (select row_number()over(order by id)rownumber,* from pagetest)a where rownumber>9900 select * from (select row_number()over(order by id)rownumber,* from pagetest)a where rownumber>9900 and rownumber<9951 select * from (select row_number()over(order by id)rownumber,* from pagetest)a where rownumber between 9901 and 9950 --写法5,在csdn上一帖子看到的,row_number() 变体,不基于已有字段产生记录序号,先按条件筛选以及排好序,再在结果集上给一常量列用于产生记录序号 select * from ( select row_number()over(order by tempColumn)rownumber,* from (select top 9950 tempColumn=0,* from pagetest where 1=1 order by id)a )b where rownumber>9900
做一个简单的大数据测试,用一百万的数据,来检测一下上面五种sql语句的执行效率时间:
create database DBTest use DBTest --创建测试表 create table pagetest ( id int identity(1,1) not null, col01 int null, col02 nvarchar(50) null, col03 datetime null ) --1万记录集 declare @i int set @i=0 while(@i<1000000) begin insert into pagetest select cast(floor(rand()*10000) as int),left(newid(),10),getdate() set @i=@i+1 end
---测试sql执行的时间语句
declare @begin_date datetime
declare @end_date datetime
select @begin_date = getdate()
<.....YOUR CODE.....>
select @end_date = getdate()
select datediff(ms,@begin_date,@end_date) as '毫秒'
经过测试,用row_number()方法效率最为高效,用时最少;