使用php日期函数时，日期转换为1969年

Why do I get 1969 when I convert the following date to Y-m-d format.

$date1="01/02/2012";
echo date('Y-m-d',$date1);

NOTE: This is php4.

You need to convert the date string to a timestamp:

echo date('Y-m-d', strtotime($date1));