Re: how do i query the type of an object?

From: Yeb Havinga <yebhavinga(at)gmail(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Mark Rostron <mrostron(at)ql2(dot)com>, "pgsql-admin(at)postgresql(dot)org" <pgsql-admin(at)postgresql(dot)org>
Subject: Re: how do i query the type of an object?
Date: 2010-08-12 08:14:59
Message-ID: 4C63AD83.3060602@gmail.com
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Tom Lane wrote:
> Mark Rostron <mrostron(at)ql2(dot)com> writes:
>
>> Is there some way to query the data-type of '<some value expression>'?
>>
>
> There's a SQL-standard construct called IS OF, and a function called
> pg_typeof, but it's not real clear whether either of those would help
> you.
>
I failed finding IS OF in the pg documentation, however,
http://farrago.sourceforge.net/design/UserDefinedTypesAndRoutines.html
had a reference to it.

postgres=# create table a(a) as select 1;
SELECT 1
postgres=# select * from a where a IS OF (integer);
a
---
1
(1 row)

While learning this somehow triggers the 'cool I just learned some new
obscure SQL trick' feeling, I am not sure if it is really useful without
CREATE TYPE foo UNDER bar.

regards,
Yeb Havinga

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