WP_query and date range filter

WP_query and date range filter

// Build the wp_query array
$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
  
$args = array(
  	'post_type' => 'post', 
  	'show_posts' => '10', 
  	'paged' => $paged
);

foreach(array('s', 'cat', 'country', 'd') as $key) {
	if(isset($_GET[$key]) && trim($_GET[$key]) !== '') { $args[$key] = $_GET[$key]; }
}

if(isset($args['s'])) { 
	// This is the date range filter
	function filter_where( $where = '' ) {
		$date_range = $_GET['d'];
		$date_range = explode("|", $date_range);
		$that_date = $date_range[0]; 
	  	$this_date = $date_range[1];							  	
	    $where .= " AND post_date >= '".$that_date."' AND post_date <= '".$this_date."' ";
	    return $where;
	}
	add_filter( 'posts_where', 'filter_where' );
	$the_query = new WP_Query($args); // WP_QUERY
	remove_filter( 'posts_where', 'filter_where' );
}

good example
but beware of using it on production, it is sql-injectable