RE: Quick question re outer joins
- From: "Powell, Mark D" <mark.powell@xxxxxxx>
- To: "'oracle-l@xxxxxxxxxxxxx'" <oracle-l@xxxxxxxxxxxxx>
- Date: Fri, 23 Jul 2004 10:17:31 -0400
If Table A is the driver and the table we always want a row to be returned
from and we join it to table B with the "(+)" on the B side of the where
clause conditions. Now Table B has 0 or more rows for every row in A. When
there is no match the row in A is still returned. When there is a match the
row in A is returned for each and every match in B just as in normal inner
join. So if 3 three rows in B that share the join keys with A you will get
2 extra rows compared to just a count(*) from A based on the A table where
conditions.
HTH -- Mark D Powell --
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx]On Behalf Of Nuno Souto
Sent: Friday, July 23, 2004 10:07 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: Re: Quick question re outer joins
jo_holvoet@xxxxxxxx apparently said,on my timestamp of 23/07/2004 6:50 PM:
> If the relationship to the new table is 1-N, it could potentially add rows
> just like a regular join, couldn't it ?
How?
If it finds a corresponding row, it puts its column value in the output.
If it doesn't, it puts a NULL there. How can that add rows?
--
Cheers
Nuno Souto
in sunny Sydney, Australia
dbvision@xxxxxxxxxxxxxxx
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