Re: date comparision ??? - Mailing list pgsql-sql

From Ross J. Reedstrom
Subject Re: date comparision ???
Date
Msg-id 20000712115556.D1487@rice.edu
Whole thread Raw
In response to Re: date comparision ???  ("sandis" <sandis@mediaparks.lv>)
List pgsql-sql
On Mon, Jul 10, 2000 at 11:52:16AM +0300, sandis wrote:
> Thanks for your input. Unfortunately, it doesn't helped..
> 
> Here is the samples.
> 
> This query works fine:
> SELECT datums_ FROM jaunumi WHERE flag = 'a' AND date_part('year',datetime
> '2000-06-02 06:11:01-07') = '2000' LIMIT 1;
> datums_
> ----------------------
> 2000-07-06 18:51:27+03
> (1 row)
> 
> But this fails, obviously because the function doesnt know the value of
> datums_:
> SELECT datums_ FROM jaunumi WHERE flag = 'a' AND date_part('year',datetime
> 'datums_') = '2000' LIMIT 1;
> ERROR:  Bad datetime external representation 'datums_'
> 
> datums_ is a timestamp field. How do i get it's value to use in date_part()
> function??
> date_part('year',datums_)   and date_part('year',datetime datums_) doesnt
> work also!

Right, that's the syntax for a datetime literal, not a cast. How about:

SELECT datums_ FROM jaunumi WHERE flag = 'a' AND date_part('year', datetime(datums_)) = 2000 LIMIT 1;

By the way, what version are you using? The functional cast is needed for 
6.5.X, but not for 7.X.

Ross

-- 
Ross J. Reedstrom, Ph.D., <reedstrm@rice.edu> 
NSBRI Research Scientist/Programmer
Computer and Information Technology Institute
Rice University, 6100 S. Main St.,  Houston, TX 77005


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