测试环境
硬件：cpu 酷睿双核t5750 内存：2g
软件:windows server 2003 + sql server 2005
ok,我们首先创建一数据库：data_test,并在此数据库中创建一表：tb_testtable
data_test
go
use data_test
go
create table tb_testtable –创建表
(id int identity(1,1) primary key,
username nvarchar(20) not null,
userpwd nvarchar(20) not null,
useremail nvarchar(40) null)
go
然后我们在数据表中插入2000000条数据:
set identity_insert tb_testtable on
declare @count int
set @count=1
while @count<=2000000
begin
insert into tb_testtable(id,username,userpwd,useremail) values(@count,’admin’,’admin888′,’lli0077@yahoo.com.cn’)
set @count=@count+1
end
set identity_insert tb_testtable off
我首先写了五个常用存储过程：
1，利用select top 和select not in进行分页，具体代码如下：
(
@pageindex int, –页索引
@pagesize int –每页记录数
)
as
begin
set nocount on;
declare @timediff datetime –耗时
declare @sql nvarchar(500)
select @timediff=getdate()
set @sql=’select top ‘+str(@pagesize)+’ * from tb_testtable where(id not in(select top ‘+str(@pagesize*@pageindex)+’ id from tb_testtable order by id asc)) order by id’
execute(@sql) –因select top后不支技直接接参数，所以写成了字符串@sql
select datediff(ms,@timediff,getdate()) as 耗时
set nocount off;
end
2,利用select top 和 select max(列键)
(
@pageindex int, –页索引
@pagesize int –页记录数
)
as
begin
set nocount on;
declare @timediff datetime
declare @sql nvarchar(500)
select @timediff=getdate()
set @sql=’select top ‘+str(@pagesize)+’ * from tb_testtable where(id>(select max(id) from (select top ‘+str(@pagesize*@pageindex)+’ id from tb_testtable order by id) as temptable)) order by id’
execute(@sql)
select datediff(ms,@timediff,getdate()) as 耗时
set nocount off;
end
3,利用select top和中间变量–此方法因网上有人说效果最佳，所以贴出来一同测试
(
@pageindex int,
@pagesize int
)
as
declare @count int
declare @id int
declare @timediff datetime
declare @sql nvarchar(500)
begin
set nocount on;
select @count=0,@id=0,@timediff=getdate()
select @count=@count+1,@id=case when @count<=@pagesize*@pageindex then id else @id end from tb_testtable order by id
set @sql=’select top ‘+str(@pagesize)+’ * from tb_testtable where id>’+str(@id)
execute(@sql)
select datediff(ms,@timediff,getdate()) as 耗时
set nocount off;
end
4,利用row_number() 此方法为sql server 2005中新的方法,利用row_number()给数据行加上索引
(
@pageindex int,
@pagesize int
)
as
declare @timediff datetime
begin
set nocount on;
select @timediff=getdate()
select * from (select *,row_number() over(order by id asc) as idrank from tb_testtable) as idwithrownumber where idrank>@pagesize*@pageindex and idrank<@pagesize*(@pageindex+1)
select datediff(ms,@timediff,getdate()) as 耗时
set nocount off;
end
5，利用临时表及row_number
(
@pageindex int, –页索引
@pagesize int –页记录数
)
as
set nocount on;
declare @ctestr nvarchar(400)
declare @strsql nvarchar(400)
declare @datediff datetime
begin
select @datediff=getdate()
set @ctestr=’with table_cte as
(select ceiling((row_number() over(order by id asc))/’+str(@pagesize)+’) as page_num,* from tb_testtable)’;
set @strsql=@ctestr+’ select * from table_cte where page_num=’+str(@pageindex)
end
begin
execute sp_executesql @strsql
select datediff(ms,@datediff,getdate())
set nocount off;
end
ok,至此，存储过程创建完毕，我们分别在每页10条数据的情况下在第2页，第1000页，第10000页，第100000页，第199999页进行测试，耗时单位：ms 每页测试5次取其平均值
存过 第2页耗时 第1000页耗时 第10000页耗时 第100000页耗时 第199999页耗时 效率排行
1用not in 0ms 16ms 47ms 475ms 953ms 3
2用select max 5ms 16ms 35ms 325ms 623ms 1
3中间变量 966ms 970ms 960ms 945ms 933ms 5
4row_number 0ms 0ms 34ms 365ms 710ms 2
4临时表 780ms 796ms 798ms 780ms 805ms 4
测试结果显示：select max >row_number>not in>临时表>中间变量
于是我对效率最高的select max方法用2分法进行了扩展，代码取自互联网，我修改了asc排序时取不到值的bug，测试结果:
2分法 156ms 156ms 180ms 470ms 156ms 1*
从测试结果来看，使用2分法确实可以提高效率并使效率更为稳定，我又增加了第159999页的测试，用时仅296ms，效果相当的不错！
下面是2分法使用select max的代码，已相当完善。
–/*—–存储过程 分页处理 浪尘 2008-9-1修改———-*/
–/*—– 对数据进行了2分处理使查询前半部分数据与查询后半部分数据性能相同 ——-*/
alter procedure proc_paged_2part_selectmax
(
@tblname nvarchar(200), —-要显示的表或多个表的连接
@fldname nvarchar(500) = ‘*’, —-要显示的字段列表
@pagesize int = 10, —-每页显示的记录个数
@page int = 1, —-要显示那一页的记录
@fldsort nvarchar(200) = null, —-排序字段列表或条件
@sort bit = 0, —-排序方法，0为升序，1为降序(如果是多字段排列sort指代最后一个排序字段的排列顺序(最后一个排序字段不加排序标记)–程序传参如：’ sorta asc,sortb desc,sortc ‘)
@strcondition nvarchar(1000) = null, —-查询条件,不需where
@id nvarchar(150), —-主表的主键
@dist bit = 0, —-是否添加查询字段的 distinct 默认0不添加/1添加
@pagecount int = 1 output, —-查询结果分页后的总页数
@counts int = 1 output —-查询到的记录数
)
as
set nocount on
declare @sqltmp nvarchar(1000) —-存放动态生成的sql语句
declare @strtmp nvarchar(1000) —-存放取得查询结果总数的查询语句
declare @strid nvarchar(1000) —-存放取得查询开头或结尾id的查询语句
declare @strsorttype nvarchar(10) —-数据排序规则a
declare @strfsorttype nvarchar(10) —-数据排序规则b
declare @sqlselect nvarchar(50) —-对含有distinct的查询进行sql构造
declare @sqlcounts nvarchar(50) —-对含有distinct的总数查询进行sql构造
declare @timediff datetime –耗时测试时间差
select @timediff=getdate()
if @dist = 0
begin
set @sqlselect = ‘select ‘
set @sqlcounts = ‘count(*)’
end
else
begin
set @sqlselect = ‘select distinct ‘
set @sqlcounts = ‘count(distinct ‘+@id+’)’
end
if @sort=0
begin
set @strfsorttype=’ asc ‘
set @strsorttype=’ desc ‘
end
else
begin
set @strfsorttype=’ desc ‘
set @strsorttype=’ asc ‘
end
——–生成查询语句——–
–此处@strtmp为取得查询结果数量的语句
if @strcondition is null or @strcondition=” –没有设置显示条件
begin
set @sqltmp = @fldname + ‘ from ‘ + @tblname
set @strtmp = @sqlselect+’ @counts=’+@sqlcounts+’ from ‘+@tblname
set @strid = ‘ from ‘ + @tblname
end
else
begin
set @sqltmp = + @fldname + ‘from ‘ + @tblname + ‘ where (1>0) ‘ + @strcondition
set @strtmp = @sqlselect+’ @counts=’+@sqlcounts+’ from ‘+@tblname + ‘ where (1>0) ‘ + @strcondition
set @strid = ‘ from ‘ + @tblname + ‘ where (1>0) ‘ + @strcondition
end
—-取得查询结果总数量—–
exec sp_executesql @strtmp,n’@counts int out ‘,@counts out
declare @tmpcounts int
if @counts = 0
set @tmpcounts = 1
else
set @tmpcounts = @counts
–取得分页总数
set @pagecount=(@tmpcounts+@pagesize-1)/@pagesize
/**//**//**//**当前页大于总页数 取最后一页**/
if @page>@pagecount
set @page=@pagecount
–/*—–数据分页2分处理——-*/
declare @pageindex int –总数/页大小
declare @lastcount int –总数%页大小
set @pageindex = @tmpcounts/@pagesize
set @lastcount = @tmpcounts%@pagesize
if @lastcount > 0
set @pageindex = @pageindex + 1
else
set @lastcount = @pagesize
–//***显示分页
if @strcondition is null or @strcondition=” –没有设置显示条件
begin
if @pageindex<2 or @page<=@pageindex / 2 + @pageindex % 2 –前半部分数据处理
begin
if @page=1
set @strtmp=@sqlselect+’ top ‘+ cast(@pagesize as varchar(4))+’ ‘+ @fldname+’ from ‘+@tblname
+’ order by ‘+ @fldsort +’ ‘+ @strfsorttype
else
begin
if @sort=1
begin
set @strtmp=@sqlselect+’ top ‘+ cast(@pagesize as varchar(4))+’ ‘+ @fldname+’ from ‘+@tblname
+’ where ‘+@id+’ <(select min(‘+ @id +’) from (‘+ @sqlselect+’ top ‘+ cast(@pagesize*(@page-1) as varchar(20)) +’ ‘+ @id +’ from ‘+@tblname
+’ order by ‘+ @fldsort +’ ‘+ @strfsorttype+’) as tbminid)’
+’ order by ‘+ @fldsort +’ ‘+ @strfsorttype
end
else
begin
set @strtmp=@sqlselect+’ top ‘+ cast(@pagesize as varchar(4))+’ ‘+ @fldname+’ from ‘+@tblname
+’ where ‘+@id+’ >(select max(‘+ @id +’) from (‘+ @sqlselect+’ top ‘+ cast(@pagesize*(@page-1) as varchar(20)) +’ ‘+ @id +’ from ‘+@tblname
+’ order by ‘+ @fldsort +’ ‘+ @strfsorttype+’) as tbminid)’
+’ order by ‘+ @fldsort +’ ‘+ @strfsorttype
end
end
end
else
begin
set @page = @pageindex-@page+1 –后半部分数据处理
if @page <= 1 –最后一页数据显示
set @strtmp=@sqlselect+’ * from (‘+@sqlselect+’ top ‘+ cast(@lastcount as varchar(4))+’ ‘+ @fldname+’ from ‘+@tblname
+’ order by ‘+ @fldsort +’ ‘+ @strsorttype+’) as temptb’+’ order by ‘+ @fldsort +’ ‘+ @strfsorttype
else
if @sort=1
begin
set @strtmp=@sqlselect+’ * from (‘+@sqlselect+’ top ‘+ cast(@pagesize as varchar(4))+’ ‘+ @fldname+’ from ‘+@tblname
+’ where ‘+@id+’ >(select max(‘+ @id +’) from(‘+ @sqlselect+’ top ‘+ cast(@pagesize*(@page-2)+@lastcount as varchar(20)) +’ ‘+ @id +’ from ‘+@tblname
+’ order by ‘+ @fldsort +’ ‘+ @strsorttype+’) as tbmaxid)’
+’ order by ‘+ @fldsort +’ ‘+ @strsorttype+’) as temptb’+’ order by ‘+ @fldsort +’ ‘+ @strfsorttype
end
else
begin
set @strtmp=@sqlselect+’ * from (‘+@sqlselect+’ top ‘+ cast(@pagesize as varchar(4))+’ ‘+ @fldname+’ from ‘+@tblname
+’ where ‘+@id+’ <(select min(‘+ @id +’) from(‘+ @sqlselect+’ top ‘+ cast(@pagesize*(@page-2)+@lastcount as varchar(20)) +’ ‘+ @id +’ from ‘+@tblname
+’ order by ‘+ @fldsort +’ ‘+ @strsorttype+’) as tbmaxid)’
+’ order by ‘+ @fldsort +’ ‘+ @strsorttype+’) as temptb’+’ order by ‘+ @fldsort +’ ‘+ @strfsorttype
end
end
end
else –有查询条件
begin
if @pageindex<2 or @page<=@pageindex / 2 + @pageindex % 2 –前半部分数据处理
begin
if @page=1
set @strtmp=@sqlselect+’ top ‘+ cast(@pagesize as varchar(4))+’ ‘+ @fldname+’ from ‘+@tblname
+’ where 1=1 ‘ + @strcondition + ‘ order by ‘+ @fldsort +’ ‘+ @strfsorttype
else if(@sort=1)
begin
set @strtmp=@sqlselect+’ top ‘+ cast(@pagesize as varchar(4))+’ ‘+ @fldname+’ from ‘+@tblname
+’ where ‘+@id+’ <(select min(‘+ @id +’) from (‘+ @sqlselect+’ top ‘+ cast(@pagesize*(@page-1) as varchar(20)) +’ ‘+ @id +’ from ‘+@tblname
+’ where (1=1) ‘ + @strcondition +’ order by ‘+ @fldsort +’ ‘+ @strfsorttype+’) as tbminid)’
+’ ‘+ @strcondition +’ order by ‘+ @fldsort +’ ‘+ @strfsorttype
end
else
begin
set @strtmp=@sqlselect+’ top ‘+ cast(@pagesize as varchar(4))+’ ‘+ @fldname+’ from ‘+@tblname
+’ where ‘+@id+’ >(select max(‘+ @id +’) from (‘+ @sqlselect+’ top ‘+ cast(@pagesize*(@page-1) as varchar(20)) +’ ‘+ @id +’ from ‘+@tblname
+’ where (1=1) ‘ + @strcondition +’ order by ‘+ @fldsort +’ ‘+ @strfsorttype+’) as tbminid)’
+’ ‘+ @strcondition +’ order by ‘+ @fldsort +’ ‘+ @strfsorttype
end
end
else
begin
set @page = @pageindex-@page+1 –后半部分数据处理
if @page <= 1 –最后一页数据显示
set @strtmp=@sqlselect+’ * from (‘+@sqlselect+’ top ‘+ cast(@lastcount as varchar(4))+’ ‘+ @fldname+’ from ‘+@tblname
+’ where (1=1) ‘+ @strcondition +’ order by ‘+ @fldsort +’ ‘+ @strsorttype+’) as temptb’+’ order by ‘+ @fldsort +’ ‘+ @strfsorttype
else if(@sort=1)
set @strtmp=@sqlselect+’ * from (‘+@sqlselect+’ top ‘+ cast(@pagesize as varchar(4))+’ ‘+ @fldname+’ from ‘+@tblname
+’ where ‘+@id+’ >(select max(‘+ @id +’) from(‘+ @sqlselect+’ top ‘+ cast(@pagesize*(@page-2)+@lastcount as varchar(20)) +’ ‘+ @id +’ from ‘+@tblname
+’ where (1=1) ‘+ @strcondition +’ order by ‘+ @fldsort +’ ‘+ @strsorttype+’) as tbmaxid)’
+’ ‘+ @strcondition+’ order by ‘+ @fldsort +’ ‘+ @strsorttype+’) as temptb’+’ order by ‘+ @fldsort +’ ‘+ @strfsorttype
else
set @strtmp=@sqlselect+’ * from (‘+@sqlselect+’ top ‘+ cast(@pagesize as varchar(4))+’ ‘+ @fldname+’ from ‘+@tblname
+’ where ‘+@id+’ <(select min(‘+ @id +’) from(‘+ @sqlselect+’ top ‘+ cast(@pagesize*(@page-2)+@lastcount as varchar(20)) +’ ‘+ @id +’ from ‘+@tblname
+’ where (1=1) ‘+ @strcondition +’ order by ‘+ @fldsort +’ ‘+ @strsorttype+’) as tbmaxid)’
+’ ‘+ @strcondition+’ order by ‘+ @fldsort +’ ‘+ @strsorttype+’) as temptb’+’ order by ‘+ @fldsort +’ ‘+ @strfsorttype
end
end
——返回查询结果—–
exec sp_executesql @strtmp
select datediff(ms,@timediff,getdate()) as 耗时
–print @strtmp
set nocount off
go
执行示例：exec proc_paged_2part_selectmax ‘tb_testtable’,’id,username,userpwd,useremail’,10,100000,’id’,0,null,’id’,0
这种测试只在单机进行，并且没有在实际开发web项目中分页测试，测试项也比较单一，所以不够全面系统，但从其效率相比上，我们可以在数据库分页算法上进行有效的控制。
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