Re: The (+) outer join operator.
Date: Thu, 1 Dec 1994 16:28:07 GMT
Message-ID: <D054Ev.2D2_at_lanier.com>
In article <D007AI.F6B_at_iglou.com>,
Phil Roberts <proberts_at_iglou.iglou.com> wrote:
>I've been told that I should be using an outer join operator (+) in an
>insert statement I am trying to run. I've read the small bit of info
>in the SQL Reference Manual about (+) but I'm still having a hard time
>understanding what it does, and why I should use it. Can someone explain
>the (+) outer join operator better than the manual?
>
One way to think of the outer join is as a tradtional table lookup.
It retrieves additional information about each row from another table using
some key value in the row. The difference with the outer join versus
the usual equi-join is this: if the additional information is *not*
available, the outer join will supply NULL values. The equi-join will
eliminate the row from the query result.
Donald E. Vick (dvick_at_lanier.com, dvick_at_crl.com) Voice: (404) 493-2194 Fax: (404) 493-2399 Received on Thu Dec 01 1994 - 17:28:07 CET