Re: [HACKERS] [7.3.x] function does not exist ... ?

[Andrew Dunstan]

Marc G. Fournier wrote:

'k, this doesn't look right, but it could be that I'm overlooking
something ...
The function I created:

CREATE FUNCTION month_trunc (timestamp without time zone) RETURNS timestamp without 
time zone
   AS 'SELECT date_trunc(''month'', $1 )'
   LANGUAGE sql IMMUTABLE;
The query that fails:

ams=# select * from traffic_logs where month_trunc(runtime) = month_trunc(now());
ERROR:  Function month_trunc(timestamp with time zone) does not exist
       Unable to identify a function that satisfies the given argument types
       You may need to add explicit typecasts
The query that succeeds:

ams=# explain select * from traffic_logs where month_trunc(runtime) = '2003-10-01';
                                       QUERY PLAN
-------------------------------------------------------------------------------------------
Index Scan using tl_month on traffic_logs  (cost=0.00..30751.90 rows=8211 width=36)
  Index Cond: (month_trunc(runtime) = '2003-10-01 00:00:00'::timestamp without time 
zone)
(2 rows)
I haven't mis-spelt anything that I can see ... is this something that is
known not to be doable?
 

Try casting now() to timestamp without time zone?

cheers

andrew

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