code: public function dateToSqlFormat($dateString) 
  	{		
      	$dateFormatter = new \IntlDateFormatter(
  			\Locale::getDefault(),
  			\IntlDateFormatter::NONE,
  			\IntlDateFormatter::NONE,
  			\date_default_timezone_get(),
  			\IntlDateFormatter::GREGORIAN,
  			"dd MMM yyyy"
      	);
      	$time = $dateFormatter->parse($dateString);
      	$date = new \DateTime();
      	$date->setTimestamp($time);
      	
      	return $date->format('Y-m-d');
     }
docs: Format from "dd MMM yyyy" to "Y-m-d"
  
  @param string $dateString
  @return string