From: | "Anibal David Acosta" <aa(at)devshock(dot)com> |
---|---|
To: | "'Tom Lane'" <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | <pgsql-performance(at)postgresql(dot)org> |
Subject: | Re: Do cast affects index usage? |
Date: | 2012-10-13 00:27:42 |
Message-ID: | 000001cda8d9$913a7770$b3af6650$@devshock.com |
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Lists: | pgsql-performance |
Because I need to get all rows where datetime is greater than (for example)
'2012-10-10 00:00:00' but ignoring timezone, so basically I need to truncate
timezone
This can be done by converting to timestamp without timezone.
-----Mensaje original-----
De: Tom Lane [mailto:tgl(at)sss(dot)pgh(dot)pa(dot)us]
Enviado el: viernes, 12 de octubre de 2012 05:39 p.m.
Para: Anibal David Acosta
CC: pgsql-performance(at)postgresql(dot)org
Asunto: Re: [PERFORM] Do cast affects index usage?
"Anibal David Acosta" <aa(at)devshock(dot)com> writes:
> I have a table with a column of type timestamp with time zone, this
> column has an index
> If I do a select like this
> select * from mytable where cast(my_date as timestamp without time
> zone) >
> '2012-10-12 20:00:00'
> this query will use the index over the my_date column?
No. The cast seems rather pointless though ...
regards, tom lane
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