ขอสอบถามผู้รู้ เรื่อง Insert DateDiff ลงในฐานข้อมูล มือใหม่ครับ

function DateDiff($strDate1,$strDate2)
{
return (strtotime($strDate2) - strtotime($strDate1))/ ( 60 * 60 * 24 ); // 1 day = 60*60*24
}
function TimeDiff($strTime1,$strTime2)
{
return (strtotime($strTime2) - strtotime($strTime1))/ ( 60 * 60 ); // 1 Hour = 60*60
}
function DateTimeDiff($strDateTime1,$strDateTime2)
{
return (strtotime($strDateTime2) - strtotime($strDateTime1))/ ( 60 * 60 ); // 1 Hour = 60*60
}
echo "Date Diff = ".DateDiff("2008-08-01","2008-08-31")."<br>";
echo "Time Diff = ".TimeDiff("00:00","19:00")."<br>";
echo "Date Time Diff = ".DateTimeDiff("2008-08-01 00:00","2008-08-01 19:00")."<br>";
?>