Re: Doing INTERVAL with NOW() versus casted timestamp

From: John Shott <shott(at)stanford(dot)edu>
To: pgsql-general(at)postgresql(dot)org
Subject: Re: Doing INTERVAL with NOW() versus casted timestamp
Date: 2013-02-16 15:45:12
Message-ID: 511FA988.6000702@stanford.edu
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Wells:

The now() function returns not only the current date, but the current
time. So, now() - 24 hours returns yesterday at this time. But,
yesterday at 00:00:00 is not greater than or equal to yesterday at the
current time (unless, of course, you happened to run this at precisely
00:00:00 ...).

I believe that if you use the current_date function, instead of now(),
and subtract 24 hours from that, then you will get the behavior that you
expect.

Good luck,

John

On 2/16/2013 7:25 AM, Wells Oliver wrote:
> Why does this give me two different results? 'created' is a date field:
>
> SELECT * FROM foo WHERE created >= '2013-02-16 00:00:00'::timestamp -
> INTERVAL '24 hours'
>
> and
>
> SELECT * FROM foo WHERE created >= NOW() - INTERVAL '24 hours'
>
> First returns the 12 rows I expect where the 'created' field is
> 2012-02-15, second returns only one.
>
> Thank you.
>

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