For execution performance

[leo6]

I was looking for performance improvement on this...
Is it possible ???

select a.col1 , a.col2
from tab1 a, tab2 b
where a.col3=b.col3
and a.col4 = <constant>

 

[dbomrrsm]

Could try swapping around the where clauses to see if that has any effect i.e.

where a.col4 = <constant>
and a.col3=b.col3

[blue]DBomrrsm[/blue]

[blue]Software code, like laws and sausages, should never be examined in production[/blue][black] - [/black][purple]Edward Tenner[/purple]

 

[vongrunt]

Swapping doesn't matter - AND operator is commutative and optimizer usually picks the least costly part to evaluate first.

Try with index on a.col3 or a.col4.

------
heisenbug: A bug that disappears or alters its behavior when one attempts to probe or isolate it
schroedinbug: A bug that doesn't appear until someone reads source code and realizes it never should have worked, at which point the program promptly stops working for everybody until fixed.

 

[JohnDTampaBay]

Check the execution plan. If you're getting a table scan or clustered index scan for either table, you may want to add an index. Good luck!

--John
-----------------------------------
Behold! As a wild ass in the desert
go forth I to do my work.
--Gurnie Hallock (Dune)