SQL Question

Hi all,

I am running a simple select from SQL*Plus to create a view on an 8i database on NT. The last statement in the query reads as follows:

and (date_termination is null OR date_termination >= to_date('01-jun-2002','dd-mon-yyyy')

If I run it this way it returns the records with date_termination null but not the records with date_termination >= 01-jun-2002. If I reverse the ordering of the clauses around the OR as in

and (date_termination >= to_date('01-jun-2002','dd-mon-yyyy') OR date_termination is null )

then it returns both the records containing null term dates and the records with term dates >= 01-jun-2002. What I don't understand is why the change in position would change the result set if the whole statement is enclosed in parens. I know that AND binds more tightly than OR but the docs say the parens should overide this. Is it an an 'unknown' value form the null that is causing the evaluation to terminate befoe the second clause is checked? I can make it do what I want but i don't understand why which is annoying.

Thank you,
mark   Received on Tue Oct 15 2002 - 21:23:14 CDT