| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | "Gordon A(dot) Runkle" <gar(at)integrated-dynamics(dot)com> |
| Cc: | pgsql-sql(at)postgresql(dot)org |
| Subject: | Re: UNION in a VIEW? |
| Date: | 2001-04-04 22:13:21 |
| Message-ID: | 12713.986422401@sss.pgh.pa.us |
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| Lists: | pgsql-sql |
"Gordon A. Runkle" <gar(at)integrated-dynamics(dot)com> writes:
> I have a number of views that I'm bringing over from DB2 which
> have UNIONs in them. Some of the UNIONs have joins.
> The views are not working as expected (I'm running 7.1RC2).
> It appears that the where clause being applied to the view
> by the user is not being distributed properly to the selects.
You're correct, an outer WHERE clause will not be pushed down into
the member selects of a UNION. (This hasn't really got anything
to do with whether a VIEW is involved.) I haven't gotten round to
convincing myself about whether that transformation is always valid,
or what conditions it needs to be valid. A TODO item for some
future release...
regards, tom lane
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