Re: order in which the AND clause used in a WHERE condition

vsathe_at_statestreet.com (Vivek_Sathe) wrote in message news:<c2fdc2d4.0310171357.75c30b78_at_posting.google.com>...
> SQL script is as follows:
>
> Select Col1 , Col2
> from Table1 T1, Table2 T2
> Where TO_NUMBER(T1.Col4) = T2.Col4
> and T2.Col5 = 'ABC'
>
> I want to know what is the order in which oracle pick up and process
> the filters given in the where-and condiiton?
>
> Pickup the data from file-block.
> Apply filter using where-and clauses
> Apply functions for the field used in where-and clauses
>
> OR
>
> Pickup the data from file-block.
> Apply functions for the field used in where-and clauses
> Apply filter using where-and clauses
>
> OR
>
> anything else?
>
> Database Version: Oracle 9i
> Operating System: SUN OS 5.8
>
> Thanks
> Vivek Sathe

Use EXPLAIN PLAN or AUTOTRACE to give you a plan - it will tell you what gets evaluated first, no guessing involved.

Good luck
Greg Received on Mon Oct 20 2003 - 07:39:09 CDT