You need to change that foreach to be keys %dateparts. As it is, it's going over both the keys and the values, and when it gets to value, it's false because that key doesn't exist yet.

foreach my $element (keys %dateparts) { ... }
[download]

local $_ = "0A72656B636148206C72655020726568746F6E41207473754A";
while(s/..$//) { print chr(hex($&)) }
[download]

sub MysqlIN {
    my %dateparts= ( YEAR => '', MONTH => '', DAY => '', @_ );
    my $element;
    foreach $element ( keys %dateparts ) {
        if (  0 < $dateparts{$element}  ) {
            die "Invalid date value";
        }
    }
    my $mysqldate= join "-", @dateparts{qw(YEAR MONTH DAY)};
    return $mysqldate;
}
[download]

"cRaZy is co01, but sometimes cRaZy is cRaZy".
                                                      - crazyinsomniac

foreach my $element ( keys %dateparts ) {
    die "No datepart!: $!" unless defined $dateparts{$element};
}
[download]

the 'exit' is redundant. if the code dies, the program is exiting.

i also don't think your assignment is going to work correctly. if you're passing in date values, you really should just use something like:

my %dateparts = @_;
[download]

assuming that your input args are in the form of:

sub MySQLIN( YEAR => '1999', DAY => '10', MONTH => '3');
[download]

the join will work even if the values to join are undefined.

But if you don't initialize the hash, then passing in no arguments won't be properly detected, for example.

        - tye (but my friends call me "Tye")

my $mysqldate = join ("-", $dateparts{YEAR}, $dateparts{MONTH}, $datep
+art{DAY});
[download]

my $mysqldate = join ("-", @dateparts{ qw(YEAR MONTH DAY) });
[download]

@dateparts{("YEAR", "MONTH", "DAY")}
[download]

($dateparts{YEAR}, $dateparts{MONTH}, $datepart{DAY})
[download]

When testing if a hash key is defined, its better to use exists.

sub MysqlIN {

# Why is that '@_' in there, are you passing in an
# array of three values?
# That's what I'll assume, so I'll change this line
#my %dateparts = ( YEAR => '', MONTH => '', DAY => '', @_, );
# To this:
my %dateparts = ( YEAR=>shift, MONTH=>shift, DAY=>shift );
my $element;

while (my ($name, $value) = each %dateparts) {
 # Number validation added
 die "Invalid value for $name" unless $value and $value=~/^\d+$/;
 # You don't need to exit, you already died!
 # exit;
}

my $mysqldate = join ("-", @dateparts{qw(YEAR MONTH DAY)});

return $mysqldate;
}
[download]