Re: TIME column manipulation/comparison hangups

On Mon, Nov 3, 2008 at 12:25 PM, Bill Moran
<wmoran@collaborativefusion.com> wrote:
> In response to "Scott Marlowe" <scott.marlowe@gmail.com>:
>
>> On Mon, Nov 3, 2008 at 12:01 PM, Bill Moran
>> <wmoran@collaborativefusion.com> wrote:
>> >
>> > I'm trying to test the time in a time column to see if it's the same
>> > minute as the current time.  I wouldn't have thought this would be
>> > difficult:
>> >
>> > WHERE TO_CHAR(now(), 'HH24MI') = TO_CHAR(time_column, 'HH24MI')
>>
>> Use date_trunc
>>
>> where date_trunc('minute',timefield)=date_trunc('minute',now());
>>
>> I might have the args backwards.
>
> Hunh ...
>
> # select date_trunc('minute','13:45:15'::time);
>     date_trunc
> --------------------
>  @ 13 hours 45 mins
> (1 row)
>
> # select date_trunc('minute','13:45:15'::time with time zone);
> ERROR:  function date_trunc(unknown, time with time zone) does not exist
> LINE 1: select date_trunc('minute','13:45:15'::time with time zone);
>               ^
> HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
>
> # select date_trunc('minute',('13:45:15'::time with time zone)::time);
>     date_trunc
> --------------------
>  @ 13 hours 45 mins
> (1 row)
>
> Curiouser and curiouser ...

Ahhh, not timestamps, but times...  You might have to add the time to
some date to run it through date_trunc.