Re: SELECT question (splitting a field)

From: Madison Kelly <linux(at)alteeve(dot)com>
To: Richard Huxton <dev(at)archonet(dot)com>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: SELECT question (splitting a field)
Date: 2007-09-04 20:00:47
Message-ID: 46DDB96F.80101@alteeve.com
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Richard Huxton wrote:
> Madison Kelly wrote:
>> nmc=> SELECT 'Y' AS local FROM domains WHERE '@'||dom_name IN
>> ('mkelly(at)test(dot)com');
>> local
>> -------
>> (0 rows)
>>
>> Not work?
>
> I don't think IN does what you think it does. It's not a substring-test,
> but a set test:
>
> SELECT 1 WHERE 'x' IN ('a','b','c','x');
> SELECT a FROM foo WHERE b IN (SELECT z FROM bar WHERE frozzled<>wamble);
>
> You could mess around with substring() and length() or I'd use LIKE.
>
> If it's just a domain you're looking for though, might be most efficient
> to strip the leading part off your value with regexp_replace().

Yeah, that was my problem. I thought I was using the section following
the '@'. =/

I've been using Postgres for a while now, but only recently getting into
some of the fancier stuff. Until now, I've usually written the program
using PgSQL so I could manipulate the data as I needed. Now I am using
PgSQL as a backend for a few other applications so I am restricted to
using PgSQL to manipulate the data.

It's all left me feeling quite n00bish again. ;)

I did figure out a query that worked:

SELECT 'Y' AS local FROM domains d, users u WHERE u.usr_dom_id=d.dom_id
AND u.usr_email||'@'||d.dom_name IN ('mkelly(at)test(dot)com');

Though this may not be the most efficient. In my case, the 'usr_email'
is the LHS of the '@' sign and 'dom_name' is the domain name. If I
wanted to use (I)LIKE, how would I have matched just the domain section
of 'mkelly(at)test(dot)com' in 'dom_name'?

I'll go read up, now that I've got some key words to search the docs on.

Thanks kindly!

Madi

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