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To: Richard Broersma <richard.broersma@gmail.com>
cc: sql pgsql <pgsql-sql@postgresql.org>
Subject: Re: Learning about WITH RECURSIVE 
In-reply-to: <396486430911041403u639c750bn488ada60822448c0@mail.gmail.com> 
References: <396486430911041403u639c750bn488ada60822448c0@mail.gmail.com>
Comments: In-reply-to Richard Broersma <richard.broersma@gmail.com>
	message dated "Wed, 04 Nov 2009 14:03:33 -0800"
Date: Wed, 04 Nov 2009 17:11:04 -0500
Message-ID: <27333.1257372664@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
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Richard Broersma <richard.broersma@gmail.com> writes:
> Can anyone one explain why a "WITH RECURSIVE" query has the same
> results regardless whether UNION or UNION ALL is specified?

Well, if the rows are all different anyway, UNION isn't going to
eliminate any ...

			regards, tom lane