Lars <lars@sscsinc.com> writes:
> What I would like to do though is aggregate by each half hour or maybe
> even 20 minutes. Does anyone know a good way to do this?
I don't have a *good* answer, but a brute-force way is
* convert timestamp to integer seconds with date_part('epoch', foo)
* round to a multiple of desired time interval
* convert back to timestamp for display via timestamp()
In the long run it seems like date_trunc ought to be more flexible
than it is...
regards, tom lane