Converting dates with PHP for DATETIME in SQL
$new_date = date( "Y-m-d H:i:s", strtotime( $old_date ) );

$timestamp = '31/05/2001 12:22:56';
$timestamp = DateTime::createFromFormat('d/m/Y H:i:s', $timestamp);
echo $timestamp->format('Y-m-d H:i:s');

$timestamp = '31/05/2001 12:22:56';
$timestamp = date_create_from_format('d/m/Y H:i:s', $timestamp);
echo date_format($timestamp, 'Y-m-d H:i:s');

function localToMysql($dateTime){
  $date_chunks = explode('/', $dateTime);
    $time_chunks = explode(' ', $date_chunks[2]);
    $final_format = $time_chunks[0] . "-" . $date_chunks[1] . "-" . $date_chunks[0] . " " . $time_chunks[1];