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Date: Sat, 22 Mar 2003 08:17:19 -0800 (PST)
From: Stephan Szabo <sszabo@megazone23.bigpanda.com>
To: Rajesh Kumar Mallah <mallah@trade-india.com>
Cc: <pgsql-sql@postgresql.org>
Subject: Re: SQL help for efficient time handling..
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On Sat, 22 Mar 2003, Rajesh Kumar Mallah wrote:

> To get current_time_id  i use a query like
> SELECT  time_id from time_dimension where sql_time=date_trunc('minute' , cast(now() as time without time zone) );
>
> it works but uses seq_scan
> Seq Scan on time_dimension  (cost=0.00..35.00 rows=5 width=4) (actual time=4.75..8.16 rows=1 loops=1)
>    Filter: ((sql_time)::interval = date_trunc('minute'::text, ((now())::time without time zone)::interval))
>  Total runtime: 8.20 msec

How about something like:

select time_id from time_dimension where sql_time=
 cast(date_trunc('minute', now()) as time);