Oracle FAQ | Your Portal to the Oracle Knowledge Grid |
Home -> Community -> Mailing Lists -> Oracle-L -> Re: Basic Database Question
Hello
Even if any one table in a select contains no data,use of outer join will retrieve rows for you.Please note that outer join operator (+) is not allowed in operand of OR or IN.
Regards
System.
|--------+----------------------->
| | "Gavin |
| | D'Mello" |
| | <gavin_d_at_tis.|
| | co.in> |
| | |
| | 05/15/02 |
| | 07:33 PM |
| | Please |
| | respond to |
| | ORACLE-L |
| | |
|--------+-----------------------> >--------------------------------------------------------| | | | To: Multiple recipients of list ORACLE-L | | <ORACLE-L_at_fatcity.com> | | cc: (bcc: systems ho/VGIL) | | Subject: Basic Database Question | >--------------------------------------------------------|
Hi I'm just about to ask a really trivial question which has never struck me before.
If i write a simple select like
select c.contentid from content c,
persusercontentassoc p,
teachercontentassoc t
where
t.contentid = c.contentid OR
p.contentid = c.contentid;
and if the table persusercontentassoc is empty no rows are returned. However, if i populate this table i get meaningful data. So what i'm asking is if any one table in a select contains no data will the select always return no rows ?
Thanks,
Gavin
-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: INET: systems_ho/VGIL_at_vguard.satyam.net.in Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Thu May 16 2002 - 00:08:25 CDT