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; }