Alvaro Herrera wrote:
> Marcin Stępnicki wrote:
>
>
>> Now I need to create a query to find hours at which each of the type can
>> start. So, if it's event A (which take 15 minutes) it can start at:
>>
>> 8:00 (to 8:15)
>> 8:15 (to 8:30)
>> ( 8:30 to 8:45 is already taken )
>> 8:45 (to 9:00)
>> 9:00 (to 9:15)
>> 9:15 (to 9:30)
>> ( 9:30 to 10:00 (9:30-9:45 and 9:45-10:00) is already taken))
>> 10:00 (to 10:15)
>>
>
> I think something like this should help you:
>
> select my_hour
> from test_events right join test_timeline on
> ((start, finish) overlaps (my_hour, my_hour + 15 * '1 minute'::interval))
> where start is null;
>
> With your test data, it shows all the times except for 8:30, 9:30 and
> 9:45.
>
Nice! And, he can run that query again, flipping the 15 to 30, to get
the list of available 30 minute gaps. That's a heck-of-a lot simpler
than the stuff I discussed earlier.
--
erik jones <erik@myemma.com>
software development
emma(r)