php convert dd-mm-yyyy to yyyy-mm-dd code example

Example 1: php convert date from dd/mm/yyyy to yyyy-mm-dd

$date = DateTime::createFromFormat('d/m/Y', "24/04/2012");
echo $date->format('Y-m-d');

Example 2: php change date format from d/m/y to y-m-d

$var = '20/04/2012';
$date = str_replace('/', '-', $var);
echo date('Y-m-d', strtotime($date));