Re: SQL Question re: AND OR with nulls

On Wed, 16 Oct 2002 11:02:30 -0600, Thomas Gaines <Thomas.Gaines_at_noaa.gov> wrote:

Sorry, my mistake, won't happen again.

>Yo Mark -
>
>What's the story with the identical postings just ten minutes apart?
>Stick with just the one, okay?
>
>TG
>
>mark_at_markme.net wrote:
>
>> 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 Wed Oct 16 2002 - 22:20:52 CDT