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List:       postgresql-sql
Subject:    Re: [SQL] Question on UNION
From:       Markus Schaber <schabi () logix-tt ! com>
Date:       2006-05-22 19:07:34
Message-ID: 44720BF6.6050109 () logix-tt ! com
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Hi, Mark,

mark.dingee@cox.net schrieb:

> I ran into something I wasn't expecting while developing a new
> application.  I have two similar tables that are occasionally unioned
> pulling only about 3 fields from each.  During my testing phase I
> noticed that the union statement was returning what appeared to be a
> distinct list rather than a pure union such as is illustrated below:

This is the documented behaviour of UNION, if you don't wand duplicate
elimination, use UNION ALL.

http://www.postgresql.org/docs/8.1/static/sql-select.html documents this
nicely.

HTH,
Schabi

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