Re: how to generate a list of distinct scalar values from a column which type is array

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
Kontakt: Heynitz: 035242/47150, D1: 0160/7141639 (mehr: -> Header)
GnuPG-ID: 0x3FFF606C, privat 0x7F4584DA http://wwwkeys.de.pgp.net