Date: September 13, 2017, 7:17 am Author: Akram Hossain
You might want to look at the strtotime and date functions.
php
$query_date ='2010-02-04';// First day of the month.
echo date('Y-m-01', strtotime($query_date));// Last day of the month.
echo date('Y-m-t', strtotime($query_date));