Re: First day of month, last day of month

Don't know whether it's better, but it's shorter.
With extract you have to make the extraction for both year and month (unless cases where either one doesn't matter)
With date_trunc('month', ...) you throw away anything smaller than month in one step.
I suppose having to call the function date_trunc twice and extract 4 times in the given example could make
the date_trunc version slightly faster.
Just wondering how many times you would have to do it before noticing the "speedup".

>>> Colin Wetherbee <cww(at)denterprises(dot)org> 2008-04-24 16:15 >>>
Frank Bax wrote:
> Frank Bax wrote:
>> Nacef LABIDI wrote:
>>> is there a better method to retrieve all the rows with dates in the
>>> current month.
>>
>> select * from mytable where extract(month from mydate) = extract(month
>> from now()) and extract(year from mydate) = extract(year from now());
>
> Sorry; I was not thinking clearly - date_trunc is better for this:
>
> select * from mytable where date_trunc('month',mydate) =
> date_trunc('month',now());

I have some code that uses extract() for this sort of thing. Would you
mind explaining how date_trunc() is better for this?

Most of my extract() results end up in <select> drop-down boxes in HTML.

Thanks.

Colin