PHP Function to convert date from mm/dd/yyyy to yyyy-mm-dd

Here is a simple Function to convert date from  mm/dd/yyyy to yyyy-mm-dd.

function convert_date($date)

{

                        if($date=='')

                        return '';

                     else

                        $dateArray=explode('/',$date);

                        return "$dateArray[2]-$dateArray[0]-$dateArray[1]";

}