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Re: postgres sql help

From: Andreas Kretschmer <akretschmer(at)spamfence(dot)net>
To: pgsql-sql(at)postgresql(dot)org
Subject: Re: postgres sql help
Date: 2011-10-16 08:11:57
Message-ID: 20111016081157.GA8614@tux (view raw or flat)
Thread:
Lists: pgsql-sql
James Bond <coolofall(at)hotmail(dot)com> wrote:

> hi, i am fairly new in postgresql, so if anyone can help me would be great
> 
> if i simply do:
> 
> select ver_no
> from version
> order by ver_no
> 
> the result will be something like this:
> 
> .1.3.1
> .1.3.2.5.
> .1.4.1.7.12
> .1.4.11.14.7.
> .1.4.3.109.1.
> .1.4.8.66.
> 
> so as you can see first 3 lines are ok, but how to make 1.4.3.109 come before
> 1.4.11 because the third level "3" is smaller than "11". i understand they are
> stored as char so i used split_part function to separate each numbers between
> "." in a separate column. but when i try to convert those column into integer,
> i am getting an error msg saying: ERROR: invalid input syntax for type numeric:
> " "
> 
> here is my code:

test=*# select * from o;
       t
---------------
 .1.3.1
 .1.3.2.5.
 .1.4.1.7.12
 .1.4.11.14.7.
 .1.4.3.109.1.
 .1.4.8.66.
(6 rows)

Time: 0,262 ms
test=*# select * from o order by split_part(t,'.',2)::int,
split_part(t,'.',3)::int, split_part(t,'.',4)::int;
       t
---------------
 .1.3.1
 .1.3.2.5.
 .1.4.1.7.12
 .1.4.3.109.1.
 .1.4.8.66.
 .1.4.11.14.7.
(6 rows)

Time: 0,403 ms


Andreas
-- 
Really, I'm not out to destroy Microsoft. That will just be a completely
unintentional side effect.                              (Linus Torvalds)
"If I was god, I would recompile penguin with --enable-fly."   (unknown)
Kaufbach, Saxony, Germany, Europe.              N 51.05082°, E 13.56889°

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