y-d-m date format convert in php

Question

Here the code,

 

$date = '03/17/2020 - 04/15/2020';

 

$pieces = explode("-", $date);

$date11= $pieces[0]; // piece1

$date12= $pieces[1]; // piece2

 

$date1 = str_replace('/', '-', $date11); 

$DATE1 = date('Y-d-m', strtotime($date1));

 

$date2 = str_replace('/', '-', $date12);

$DATE2= date("Y-m-d", strtotime(preg_replace('/[^A-Za-z0-9\-]/', '',$date2)));

echo $DATE1; //2020-03-17

echo $DATE2;//1970-01-01

 

Output:    $DATE1 : 2020-03-17

                $DATE2: 1970-01-01

 

 Please advice.