สอบถามเรื่องการเช็ควันของ PHP แบบ between คล้ายๆ SQL หน่อยครับผม

<?php
	function compareDate($date1,$date2) {
		$arrDate1 = explode("-",$date1);
		$arrDate2 = explode("-",$date2);
		$timStmp1 = mktime(0,0,0,$arrDate1[1],$arrDate1[2],$arrDate1[0]);
		$timStmp2 = mktime(0,0,0,$arrDate2[1],$arrDate2[2],$arrDate2[0]);

		if ($timStmp1 == $timStmp2) {
			echo "\$date = \$date2";
		} else if ($timStmp1 > $timStmp2) {
			echo "\$date > \$date2";
		} else if ($timStmp1 < $timStmp2) {
			echo "\$date < \$date2";
		}
	}
	echo compareDate("2004-01-06","2004-05-06");
?>