Re: Getting number of days in a month

Here's my perl implementation:

#######################################
#
# lastday( month, year (4 digit) )
#
# Returns: last day of the month
#
#######################################

sub lastday {
my $month=shift;
my $year= shift;

$month--;

my @days = (31,0,31,30,31,30,31,31,30,31,30,31);

if($days[$month] != 0){
return $days[$month];
} else {
# It's Feb, test for leap year
if($year % 4 != 0){
return 28;
} elsif($year % 400 == 0){
return 29;
} elsif($year % 100 == 0){
return 28;
} else {
return 29;
}
}
}

Ken Causey
ineffable

At 02:26 PM 4/12/00 +0200, you wrote:
>To obtain the number of days in a month, I wrote this function:
>
>CREATE FUNCTION dayCountOfMonth(datetime) RETURNS float AS
>' DECLARE
> theDate ALIAS FOR $1;
> monthStart date;
> monthEnd date;
> BEGIN
> monthStart := DATE_TRUNC(''month'', theDate);
> monthEnd := monthStart + ''1 month''::timespan - ''1 day''::timespan;
> RETURN DATE_PART(''doy'', monthEnd) - DATE_PART(''doy'', monthStart) + 1;
> END;
>' LANGUAGE 'PL/pgSQL';
>
>It seems to work, except with the month of October (10).
>
>dayCountOfMonth('1997-10-1') => 30
>dayCountOfMonth('1998-10-1') => 30
>dayCountOfMonth('1999-10-1') => 31
>dayCountOfMonth('2000-10-1') => 30
>dayCountOfMonth('2001-10-1') => 30
>dayCountOfMonth('2002-10-1') => 30
>dayCountOfMonth('2003-10-1') => 30
>dayCountOfMonth('2004-10-1') => 31
>
>Just one question: WHY??????
>(Note: no trouble with February)
>
>Is there a function that give the number of days of a month?
>
>Thanks,
>
>Guillaume Perréal - Stagiaire MIAG
>Cemagref (URH), Lyon, France
>Tél: (+33) 4.72.20.87.64
>
>