Date:         Sat, 29 Sep 2007 20:58:15 -0700
Reply-To:     Patrick <patrick.matter@GMX.CH>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Patrick <patrick.matter@GMX.CH>
Organization: http://groups.google.com
Subject:      Re: OUTER JOIN and order of WHERE Clause processing
Comments: To: sas-l@uga.edu
In-Reply-To:  <1191078647.689691.106070@19g2000hsx.googlegroups.com>
Content-Type: text/plain; charset="us-ascii"

Hi Hari
I'm also working through this training. Are you happy with the
response times?

Quite interesting your findings. I think that the note for the outer
join is wrong.

I found quite an interesting SUGI paper: http://www2.sas.com/proceedings/sugi30/101-30.pdf

Using the SQL option _method as described in this paper, your code
generates the following log messages:

First SQL:
      sqxslct
          sqxfil
              sqxjm
                  sqxsort
                      sqxsrc( SASUSER.FLIGHTSCHEDULE(alias = F) )
                  sqxsort
                      sqxsrc( SASUSER.PAYROLLCHANGES(alias = P) )

Second SQL:
      sqxslct
          sqxjm
              sqxsort
                  sqxsrc( SASUSER.FLIGHTSCHEDULE(alias = F) )
              sqxsort
                  sqxsrc( SASUSER.PAYROLLCHANGES(alias = P) )


This two SQL differ only in one step which comes in the very end:
sqxfil     ...and sqxfil means "filter rows"

Conclussion: The left outer join is processed first, the where clause
subsets the result of the join.

Very curious what other more experienced SAS/SQLers will answer.

Patrick