Bruno Wolff III <bruno@xxxxxxxx> writes: > On Thu, Mar 08, 2007 at 20:32:22 -0300, > Jorge Godoy <jgodoy@xxxxxxxxx> wrote: >> Alvaro Herrera <alvherre@xxxxxxxxxxxxxxxxx> writes: >> >> As I said, it is easy with a function. :-) I was just curious to see if we >> had something like Oracle's NEXT_DAY function or something like what I >> described (SET BOW=4; -- makes Thursday the first day of week): > > If you are actually using "date" you can get the effect you want by adding > a constant integer to the date in the date_trunc function. That seems > pretty easy. I couldn't see where to specify that integer. Or, if it to sum it up to the date, something that calculates it automatically. http://www.postgresql.org/docs/8.2/interactive/functions-datetime.html#FUNCTIONS-DATETIME-TRUNC Adding an integer I'd still have to write the verifications (such as the one I mention below for Oracle's NEXT_DATE()) to get the desired result. Just to repeat my question: (I don't want to write a function, I can do that pretty easily... And I was asking if there existed some feature on the database that... It's just a curiosity) Given a date X it would return me the first day of the week so that I can make this first day an arbitrary day, e.g. Friday or Wednesday. Oracle's NEXT_DAY() gets closer to that, but would still require a few operations (checking if the returned date is before the given date or if after then subtract one week from this returned value, kind of a "PREVIOUS_DATE()"...). With a function I could make it easily, but then I'd have to wrap all calculations with that... It was just something to make life easier. From the answers I'm getting I see that there's no way to do that without a function and that I'm not missing any feature on PG with regards to that ;-) -- Jorge Godoy <jgodoy@xxxxxxxxx>
