Re: casting character varying to integer - order by numeric

Check out the function to_number()

In particular here's an example...
If a field named section is text containing numbers:
ORDER BY to_number(t.section, text(99999999))

If the field can also contain non-numerals such as 3a, 3b, and you want
3a to show first then do this:
ORDER BY to_number(t.section, text(99999999)), t.section

And if the field section can actually START with an alpha, then to
prevent to_number from failing do this:
to_number(textcat('0', t.section), text(99999999)), t.section

Terry

Bryce W Nesbitt wrote:
> How can I force a character field to sort as a numeric field?
> I've got something like this:
>
> Postgres=> SELECT username,last_name
> FROM eg_member ORDER BY username;
> ----------+-----------
> 0120 | Foley
> 1 | Sullivan
> 10 | Guest
> 11 | User
> (5 rows)
>
> (I can't change the field type). I tried:
>
> SELECT username,last_name
> FROM eg_member ORDER BY username::integer;
>
> But postgres 7 rejects this with "ERROR: cannot cast type character
> varying to integer". Is there a way to force numeric sort order? I
> tried a variety of functions, such as to_char() and convert() without
> any luck. Thanks for your insight!
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 2: Don't 'kill -9' the postmaster
>

--
Terry Fielder
terry(at)greatgulfhomes(dot)com
Associate Director Software Development and Deployment
Great Gulf Homes / Ashton Woods Homes
Fax: (416) 441-9085