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"Jeremy" <jeremy0505_at_gmail.com> schreef in bericht
news:MPG.214b41da4e682a7398a49e_at_news.individual.net...
> In article <46e01453$0$233$e4fe514c_at_news.xs4all.nl>, Shakespeare says...
>> > select foo.pk, foo.data
>> > from foo
>> > where exists ( select null from bar where foo.pk = bar.fk );
>> >
>>
>> I would not use select null here... It works, but I have seen some
>> discussions about null before in this group ;-)
>>
>>
>
> Can you elaborate on that? Surely it doesn't matter what is selected -
> it's a case of if the subquery returns 0 rows or not?
>
> --
> jeremy
Jeremy,
you're right! But in programs I usually see select '1' from table (and one
dba consistently used select '8', don't know why, doesn't matter..) . Select
null from table works (at the moment) but there has been a discussion about
null and compatibility of the Oracle null with other DB's and languages in
this group.
If you have quality assurance in your project, the QA will start asking
things like 'Are you sure this will keep working?': null is a QA-trigger....
If you use '1' no one will ask any questions.
Again: I know ths works (even in 11g!) but I would avoid any discussion (like this one) and use select '1' ....
Not a big issue however... but the discussion got really out of control...
See
http://groups.google.nl/group/comp.databases.oracle.server/browse_thread/thread/9fe9df601a89bfa
Shakespeare Received on Fri Sep 07 2007 - 06:37:10 CDT