Postgres Pro
Downloads
Home   >   mailing lists

Thread: Query TIME ZONE

Query TIME ZONE

From
"Raman"
Date:
Hi All,
I have a query regarding Time Zone Interval
 
QUERY:
"select current_time AT TIME ZONE INTERVAL '+5:30'"
it is running fine
 
BUT
When I take the value of interval from DB table like:
 
"select current_time AT TIME ZONE INTERVAL time_difference from customer_events"
 
here : time_difference - is my varchar column in the table customer_events. This gives me errors " parse error at or near "time_difference" at character 43 "
 
I tried to type cast it time_difference::text etc but it in vain.
 
Pls help me ... its realy urgent.
 
Thanks in advance
 
Raman Garg
 
 
 
 
 
 

Re: Query TIME ZONE

From
Tom Lane
Date:
"Raman" <ramang@smartdatainc.com> writes:
> [ okay: ]
> "select current_time AT TIME ZONE INTERVAL '+5:30'"
> [ not okay: ]
> "select current_time AT TIME ZONE INTERVAL time_difference from customer_events"

"TIME ZONE INTERVAL" is not a SQL construct.  You have misunderstood the
interaction of two different SQL constructs:timestamp AT TIME ZONE timezonespecINTERVAL 'interval-literal'
One of the possible forms of "timezonespec" in the AT TIME ZONE operator
is an interval value, so your first example works fine.  Your second
example does not work because the INTERVAL 'foo' construct is only for
simple literal constants.

> here : time_difference - is my varchar column in the table customer_events.

Why are you using varchar rather than an interval column?  An interval
value would work directly in this construct and would provide some
checking that entered values are sane.

If you are absolutely intent on using varchar as the column datatype,
you can do a run-time cast like this:select current_time AT TIME ZONE "interval"(time_difference) from customer_events
but don't complain when the query fails because some rows contain
time_difference strings that don't look like legal interval values...
        regards, tom lane

Re: Query TIME ZONE

From
"Raman Garg"
Date:
Thanks Tom it worked  for me...
yes I got it wrong.. thanks for the correction.

thanks a lot..
-- Raman

----- Original Message ----- 
From: "Tom Lane" <tgl@sss.pgh.pa.us>
To: "Raman" <ramang@smartdatainc.com>
Cc: <pgsql-sql@postgresql.org>
Sent: Wednesday, January 28, 2004 11:28 AM
Subject: Re: [SQL] Query TIME ZONE


> "Raman" <ramang@smartdatainc.com> writes:
> > [ okay: ]
> > "select current_time AT TIME ZONE INTERVAL '+5:30'"
> > [ not okay: ]
> > "select current_time AT TIME ZONE INTERVAL time_difference from
customer_events"
>
> "TIME ZONE INTERVAL" is not a SQL construct.  You have misunderstood the
> interaction of two different SQL constructs:
> timestamp AT TIME ZONE timezonespec
> INTERVAL 'interval-literal'
> One of the possible forms of "timezonespec" in the AT TIME ZONE operator
> is an interval value, so your first example works fine.  Your second
> example does not work because the INTERVAL 'foo' construct is only for
> simple literal constants.
>
> > here : time_difference - is my varchar column in the table
customer_events.
>
> Why are you using varchar rather than an interval column?  An interval
> value would work directly in this construct and would provide some
> checking that entered values are sane.
>
> If you are absolutely intent on using varchar as the column datatype,
> you can do a run-time cast like this:
> select current_time AT TIME ZONE "interval"(time_difference) from
customer_events
> but don't complain when the query fails because some rows contain
> time_difference strings that don't look like legal interval values...
>
> regards, tom lane
>