在这里,我在内部得到一个性能问题加入对庞大的数据为我的查询,如下所示的查询性能:SQL Server 2008中:使用内部连接
例子:
/* Creating table */
create table xyz
(
colp1 nvarchar(10),
colp2 nvarchar(10),
coldt date,
coltm datetime,
coldr integer
);
/* Inserting records */
insert into xyz values('A','B','2014-08-02','10:00:00',50);
insert into xyz values('A','C','2014-08-02','11:08:08',120);
insert into xyz values('A','B','2014-08-02','11:08:55',160);
insert into xyz values('A','D','2014-08-03','09:00:15',180);
insert into xyz values('A','E','2014-08-04','11:00:10',600);
insert into xyz values('A','F','2014-08-04','11:05:50',320);
.
.
upto 50000
/* Query */
declare @testtable table(dt date,st time,et time)
insert into @testtable select coldt,coltm,DATEADD(ss,coldr,coltm) from xyz
select distinct colp1,colp2,coldt,
coltm from xyz as x
inner join
@testtable as t on convert(varchar,x.coltm,108) > t.st and
convert(varchar,x.coltm,108)< t.et;
获得非常多的时间来对上面的查询执行大量数据。
您尚未在连接列上设置任何索引。这可能有帮助。 – stakx 2014-09-03 05:47:09
我的猜测是你的连接条件是非可变的:convert(varchar,x.coltm,108)> t.st和convert(varchar,x.coltm,108)
2014-09-03 05:53:07