Query for optimization

[leo6]

Could this query run better ?

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

a.col3=b.col3 is required because we need the output when a.col3 has a matching value for b.col3

 

[mrdenny]

There are a couple of other ways that you could write this query. However they won't improve performance any.

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

or

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

Denny
MCSA (2003) / MCDBA (SQL 2000)

--Anything is possible. All it takes is a little research. (Me)

http://www.mrdenny.com

(My very old site)

 

[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>

 

[Catadmin]

Have you checked the Estimated Execution Plan for this query? If not, open it in QA and do so. You might also want to run a Trace on it while executing the query so you can run the Index Tuning Wizard which might help you improve performance.



Catadmin - MCDBA, MCSA
Beware the error of pre-emptive poultry inventory!

 

[NorthNone]

Beware the error of pre-emptive poultry inventory!
is
Don't count your chickens before they hatch??????

---------------------------------------
The customer may not always be right, but the customer is ALWAYS the customer.

 

[Catadmin]

Yep. You wouldn't believe how many people at my workplace can't figure that one out. @=)



Catadmin - MCDBA, MCSA
Beware the error of pre-emptive poultry inventory!