|
|
Posted by Dan Guzman on 07/02/07 11:05
> Yes, but when left and inner join returns same results - left is faster
Can you post an example (DDL and sample data) that illustrates this
behavior, including with the execution plans?
I can see how this might happen in cases where the inner join uses an
execution plan that turns out to be sub-optimal. This could occur because
statistics are stale or the disk subsystem is unusually biased in favor of
scans (often used on outer joins). However, I think using LEFT JOINs
instead of INNER JOINs is not the proper solution.
--
Hope this helps.
Dan Guzman
SQL Server MVP
"news.onet.pl" <wkrugiolka@poczta.onet.pl> wrote in message
news:f6aa7t$e7p$1@news.onet.pl...
>> For starters, an outer join (such as left join) will only return the
>> same result as an inner join if no rows from the outer table would be
>> eliminated when running the inner join.
>
> Yes, but when left and inner join returns same results - left is faster
> (probably because it doesn't check the dependencies - just join results)
> We use left join instead inner in situations we know that inner join will
> not cut results....
>
>
> Regards, Wojtas
>
>
Navigation:
[Reply to this message]
|