SQL语句执行时间的计算问题

[wengyuli]

我想优化SQL语句，于是就做了计算SQL执行时间,朋友们有什么好的计算执行时间的方法请告知，谢谢。
下面的计算时间我写的有问题，报错了，所用方法是：

declare @date1 datetime
declare @date2 datetime
select @date1=getdate()
--测试语句
select @date2=getdate()
select datediff(millisecond, @date1, @date2) as 执行时间
--结果是毫秒数

下面的这个句子里，我声明的变量@date1 ,@date2 在使用中出错了，请朋友们帮忙改一下

-- 年级排名和班级排名
declare @sql varchar(4000),@nclassid int ,@nexamid int , @date1 datetime ,@date2 datetime
select @sql='' select @nclassid=32 select @nexamid=17
select @sql=@sql+'max(case scoursename when '''+scoursename+''' then descore else 0 end) '+scoursename+','
from (select distinct scoursename from t_card_course where id in (select ncourseid from t_card_examcou where nclassid =+@nclassid and nexamid=+@nexamid )) a  
exec(' 
select '+@date1+'=(getdate())

select nclassid, name  姓名,'+ @sql+ 'sum(descore) 总分
into #temp 
from ( 
 select b.nclassid,b.name,a.descore,c.scoursename from t_card_score a,t_stu b,t_card_course c,t_card_examcou d 
 where a.nstuid=b.id and a.ncouexamid in
 (select id from t_card_examcou where nclassid in (select id from t_card_class where ngradeid =(select ngradeid from t_card_class where id='+@nclassid+' and nschoolid=(select nschoolid from t_card_class where id='+@nclassid+')))  and nexamid='+@nexamid+' ) 
and a.ncouexamid=d.id and d.ncourseid=c.id group by b.nclassid,b.name,a.descore,c.scoursename )as a
 group by name,nclassid 
select *,班级名次=(select count(总分) from #temp where 总分>y.总分 and nclassid=y.nclassid)+1 into #tempclass from #temp y  order by 班级名次 
select *,年级名次 =(select count(总分) from #tempclass where 总分>x.总分)+1 into #tempok from #tempclass x where nclassid ='+@nclassid+' order by 班级名次
alter table #tempok drop column nclassid
select * from #tempok

select '+@date2+'=getdate()
select datediff(millisecond, '+@date1+', '+@date2+')
')

[-狙击手-]

exec(' 
select '+@date1+'=(getdate())

select nclassid, name  姓名,'+ @sql+ 'sum(descore) 总分
into #temp 
from ( 
 select b.nclassid,b.name,a.descore,c.scoursename from t_card_score a,t_stu b,t_card_course c,t_card_examcou d 
 where a.nstuid=b.id and a.ncouexamid in
 (select id from t_card_examcou where nclassid in (select id from t_card_class where ngradeid =(select ngradeid from t_card_class where id='+@nclassid+' and nschoolid=(select nschoolid from t_card_class where id='+@nclassid+')))  and nexamid='+@nexamid+' ) 
and a.ncouexamid=d.id and d.ncourseid=c.id group by b.nclassid,b.name,a.descore,c.scoursename )as a
 group by name,nclassid 
select *,班级名次=(select count(总分) from #temp where 总分>y.总分 and nclassid=y.nclassid)+1 into #tempclass from #temp y  order by 班级名次 
select *,年级名次 =(select count(总分) from #tempclass where 总分>x.总分)+1 into #tempok from #tempclass x where nclassid ='+@nclassid+' order by 班级名次
alter table #tempok drop column nclassid
select * from #tempok

select '+@date2+'=getdate()
select datediff(millisecond, '''+@date1+''', '''+@date2+''')
')

[wsh236]

如果是2005可以选择包括实际的执行计划，这样就可以知道你的语句哪里用时最多了。

[wengyuli]

 -- 年级排名和班级排名
declare @sql varchar(4000),@nclassid int,@nexamid int,@date1 datetime,@date2 datetime
select @sql='' select @nclassid=38 select @nexamid=19
select @sql=@sql+'max(case scoursename when '''+scoursename+''' then descore else 0 end) '+scoursename+','
from (select distinct scoursename from t_card_course where id in (select ncourseid from t_card_examcou where nclassid =+@nclassid and nexamid=+@nexamid )) a  

exec(' 
select '+@date1+'=(getdate())

select nclassid, name  姓名,'+ @sql+ 'sum(descore) 总分
into #temp 
from ( 
 select b.nclassid,b.name,a.descore,c.scoursename from t_card_score a,t_stu b,t_card_course c,t_card_examcou d 
 where a.nstuid=b.id and a.ncouexamid in
 (select id from t_card_examcou where nclassid in (select id from t_card_class where ngradeid =(select ngradeid from t_card_class where id='+@nclassid+' and nschoolid=(select nschoolid from t_card_class where id='+@nclassid+')))  and nexamid='+@nexamid+' ) 
and a.ncouexamid=d.id and d.ncourseid=c.id group by b.nclassid,b.name,a.descore,c.scoursename )as a
 group by name,nclassid 
select *,班级名次=(select count(总分) from #temp where 总分>y.总分 and nclassid=y.nclassid)+1 into #tempclass from #temp y  order by 班级名次 
select *,年级名次 =(select count(总分) from #tempclass where 总分>x.总分)+1 into #tempok from #tempclass x where nclassid ='+@nclassid+' order by 班级名次
alter table #tempok drop column nclassid
select * from #tempok

select '+@date2+'=(getdate())
select datediff(millisecond, '''+@date1+''', '''+@date2+''')
')

按照狙击手的方法我执行了一下，说是两个时间取值时
报错：“‘=’附近出现错误”

[wengyuli]

顶上去

[LONGZHEZHILONG]

路过