Index on timestamp to date field

Lists: pgsql-general
From: "Patrick Hatcher" <PHatcher(at)macys(dot)com>
To: pgsql-general(at)postgresql(dot)org
Subject: Index on timestamp to date field
Date: 2003-10-13 20:49:07
Message-ID: OFF4DD9C81.1DB45A63-ON88256DBE.00713BDB-88256DBE.00730621@fds.com
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I have a timestamp field where I find I'm doing a lot of searching by date
(YYYY-MM-DD) or using this field as a match to another table that has a
date format. I wanted to create an index on the timestamp field using a
date format. Is this possible? I tried:
CREATE INDEX test_2 ON table1 USING btree to_char(field2, 'MM-DD-YYYY');
but I get an error message error at or new to_char

TIA

Patrick Hatcher
Macys.Com
Legacy Integration Developer
415-422-1610 office
HatcherPT - AIM

From: Bruno Wolff III <bruno(at)wolff(dot)to>
To: Patrick Hatcher <PHatcher(at)macys(dot)com>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: Index on timestamp to date field
Date: 2003-10-14 02:10:30
Message-ID: 20031014021030.GA32083@wolff.to
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On Mon, Oct 13, 2003 at 13:49:07 -0700,
Patrick Hatcher <PHatcher(at)macys(dot)com> wrote:
> I have a timestamp field where I find I'm doing a lot of searching by date
> (YYYY-MM-DD) or using this field as a match to another table that has a
> date format. I wanted to create an index on the timestamp field using a
> date format. Is this possible? I tried:
> CREATE INDEX test_2 ON table1 USING btree to_char(field2, 'MM-DD-YYYY');
> but I get an error message error at or new to_char

You can't create general functional indexes until 7.4.
However you might be able to use an index on the timestamp if you cast
the character strings to a timestamp value.

From: Jeff <threshar(at)torgo(dot)978(dot)org>
To: Patrick Hatcher <PHatcher(at)macys(dot)com>
Cc: "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org>
Subject: Re: Index on timestamp to date field
Date: 2003-10-14 12:53:36
Message-ID: Pine.BSF.4.44.0310140851410.1994-100000@torgo.978.org
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On Mon, 13 Oct 2003, Patrick Hatcher wrote:

> I have a timestamp field where I find I'm doing a lot of searching by date
> (YYYY-MM-DD) or using this field as a match to another table that has a
> date format. I wanted to create an index on the timestamp field using a
> date format. Is this possible? I tried:
> CREATE INDEX test_2 ON table1 USING btree to_char(field2, 'MM-DD-YYYY');
> but I get an error message error at or new to_char
>
> TIA
>

So you don't want a oh. lets call it a "real index" on the timestamp
field?

create index ts_index on mytable(mytimestamp);

Or can you not change the way the dates are input?

Or is the "mytimestamp" field a varchar containing a date string?

--
Jeff Trout <jeff(at)jefftrout(dot)com>
http://www.jefftrout.com/
http://www.stuarthamm.net/