From: A. Kretschmer <andreas.kretschmer@schollglas.com>
To: pgsql-sql@postgresql.org
Subject: Re: how to generate a list of distinct scalar values from a column which type is array
Date: Thu, 22 Feb 2007 14:25:36 +0100
Message-ID: <20070222132536.GE15488@a-kretschmer.de> (raw)
In-Reply-To: <2cfc7c940702211021u1ba47031l25112a69cfb18338@mail.gmail.com>
References: <2cfc7c940702211021u1ba47031l25112a69cfb18338@mail.gmail.com>
am Wed, dem 21.02.2007, um 19:21:09 +0100 mailte Sergio Andreozzi folgendes:
> Dear all,
>
> given a column which type is for instance varchar(20)[], is there any SQL
> command that let me generate the list of distinct scalar values?
>
>
> e.g.:
> col1
> row 1: (aaa, bb, c)
> row 2: (dddd, eeee)
> row 3: (aaa, eeee)
>
> the query should return:
>
> aaa
> bb
> c
> dddd
> eeee
Okay, next solution:
test=*# select * from a;
c
-------------
{aaa,bb,c}
{dddd,eeee}
{aaa,eeee}
(3 rows)
test=*# select distinct c[s] from a, generate_series(1,3)s where c[s] is not null;
c
------
aaa
bb
c
dddd
eeee
(5 rows)
You need to know the greatest upper dimension of the array, in this case
3, for the generate_series - function.
Andreas
--
Andreas Kretschmer
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Cc: andreas.kretschmer@schollglas.com
Subject: Re: how to generate a list of distinct scalar values from a column which type is array
In-Reply-To: <20070222132536.GE15488@a-kretschmer.de>
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