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Re: BUG #5469: regexp_matches() has poor behaviour and more poor documentation

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: Bruce Momjian <bruce(at)momjian(dot)us>
Cc: Robert Haas <robertmhaas(at)gmail(dot)com>, Daniele Varrazzo <daniele(dot)varrazzo(at)gmail(dot)com>, pgsql-bugs(at)postgresql(dot)org
Subject: Re: BUG #5469: regexp_matches() has poor behaviour and more poor documentation
Date: 2010-06-03 14:40:47
Message-ID: 201006031440.o53EelZ12335@momjian.us (view raw or flat)
Thread:
Lists: pgsql-bugs
Bruce Momjian wrote:
> Robert Haas wrote:
> > On Mon, May 31, 2010 at 10:11 AM, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
> > > Robert Haas wrote:
> > >> On Sat, May 29, 2010 at 5:00 PM, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
> > >> > I have updated the patch, attached, to clarify that this returns text
> > >> > arrays, and that you can force it to always return one row using
> > >> > COALESCE() and a '|' pattern (the later suggested by Daniele Varrazzo).
> > >>
> > >> I don't find this part to be something we should include in the
> > >> documentation. ?If we want to include a workaround, how about defining
> > >> a non-SRF that just calls the SRF and returns the first row?
> > >
> > > Remember this has to return one row for no matches, so a simple SRF will
> > > not work. ?I also have not seen enough demand for another function. ?A
> > > single doc mention seemed the appropriate level of detail for this.
> > 
> > Well, we can debate later whether to add another function to core, but
> > what I meant was that the user having the problem could create a
> > user-defined function that calls regexp_matches() and returns the
> > first row, or NULL.
> > 
> > But actually here's an even simpler workaround, which is IMHO less
> > ugly than the original one:
> > 
> > SELECT foo, bar, (SELECT regexp_matches(bar, pattern)) FROM table;
> 
> Good idea.   Simplified patch attached.

Applied.

-- 
  Bruce Momjian  <bruce(at)momjian(dot)us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + None of us is going to be here forever. +

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