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Re: Querying now()

From: Michael Glaesemann <grzm(at)myrealbox(dot)com>
To: A Gilmore <agilmore(at)shaw(dot)ca>
Cc: pgsql-novice <pgsql-novice(at)postgresql(dot)org>
Subject: Re: Querying now()
Date: 2004-12-20 00:57:22
Message-ID: 1B15B3D8-5222-11D9-93E5-000A95C88220@myrealbox.com (view raw or flat)
Thread:
Lists: pgsql-novice
On Dec 20, 2004, at 9:05, A Gilmore wrote:

> Id like my application to do something like this :
>
> SELECT now() AS currentTime WHERE currentTime < '$timestamp';
>
> So if it returns a row Id know $timestamp is not in the past.  However 
> when you run this it simply says 'ERROR:  column "currentTime" does 
> not exist'.

AFAIK, SELECT clause aliases are not available to any other part of the 
query: it's looking for a column called currentTime, but there isn't 
one in the FROM clause tables. Then again, you don't even have a FROM 
clause. :) In general, it's best to show the exact query you're trying 
and the error messages you're getting--and if possible, reduce it to a 
test case that still exhibits the problem.

You probably want something like:

SELECT foo FROM bar WHERE current_timestamp < baz;

( current_timestamp is the SQL standard spelling of the PostgreSQL 
alternative now(). )

Also note that all identifiers are converted to lowercase unless 
double-quoted. PostgreSQL sees currentTime as currenttime.

Hope this helps.


Michael Glaesemann
grzm myrealbox com


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