Re: Dividing (and rounding) a date?

Neal Lindsay <neal(dot)lindsay(at)peaofohio(dot)com> writes:
> I am trying to create a query that, given a date, will return the
> beginning-of-pay-period date. Our pay periods last two weeks and begin on
> Mondays. I can't seem to divide or find the modulus of any date or
> interval types. Does anyone have any suggestions?

Hmm, I see how to get back to the most-recent Monday:

regression=# select now()::date - date_part('dow', now()) + 1;
?column?
------------
2001-07-30
(1 row)

but there's no date_part function that would give you two-week
intervals. I think you'll have to use date_part('epoch') to extract
the time as a Unix timestamp (seconds since 1-1-1970), do arithmetic
on that, and cast the result back to an SQL timestamp. Ugh.

regards, tom lane