logic behind this....

logical.php

<?php 
function basext_bookings_query( $query ) {
if (!is_admin()){
    if(isset($_REQUEST['checkin_date'])) {
        $from_date  =   $_REQUEST['checkin_date'];
		$from_date = date("Y-m-d", strtotime($from_date));
    }

    if(isset($_REQUEST['checkout_date'])) {
        $to_date    =   $_REQUEST['checkout_date'];
		$to_date    = date("Y-m-d", strtotime($to_date));
    }
    global $wpdb;
	global $no_match_ids;
    $query_cus = "SELECT * FROM wp_postmeta WHERE meta_key = '_wc_booking_availability'";
    $results = $wpdb->get_results($query_cus);
    if(!empty($results)) {
			
        foreach($results as $cfs) {
			$posters = $cfs->post_id; // post ID
            $un_data = unserialize($cfs->meta_value); // meta_values
			$un_data = $un_data[0]; // first level
			//$postID = $un_data->post_id;
			$first_date = $un_data['from'];
			$sec_date = $un_data['to'];
            $date_from  = date("Y-m-d", strtotime($first_date)); // from date stored in meta values
            $date_to    = date("Y-m-d", strtotime($sec_date)); // to date stored in meta values
			
		if ($date_from = '1970-01-01') {
				$no_match_ids = $posters; 
				print_r($no_match_ids);echo ' <-- this is one<br/>';// . $date_from . ' v ' . $from_date . '<br />';
			}
		//		if (($date_from < $from_date)) {
				
     
//            print_r($date_to);echo '<br />';
            /*echo $from_date;
            echo "<br>";
            echo $date_form;
            echo "<br>";
            echo $to_date;
            echo "<br>";
            echo $date_to;
            echo "<br>";*/
         if (!($date_from <= $from_date)){ //&& $to_date<=$date_to) {
                if( $query->is_main_query() & !$query->is_feed() && !is_admin() && is_post_type_archive( 'product' )) {
                    $meta_query = array(
                        array(
                            'key'       =>  '_wc_booking_qty',
                            'type'      =>  'numeric',
                            'value'     =>  1,
                            'compare'   =>  '>='
                        ),
                        /*array(
                            'key' => '_wc_booking_availability',
                            'value' => $date_form,
                            'compare' => '>=',
                            ),
                        array(
                            'key' => '_wc_booking_availability',
                            'value' => $date_to,
                            'compare' => '<=',
                            ),*/
                    );
					//setup_postdata($match_ids);
					$query->set('post_type', 'product');
                    $query->set( 'meta_query', $meta_query );
                    $query->set( 'order', 'ASC' );
                    $query->set( 'posts_per_page', '4' );
					$query->set('post__not_in', $no_match_ids);
                }
            }
			
       }
    } // get_results
	} // !is_admin
}



 echo $GLOBALS['wp_query']->request;



add_action( 'pre_get_posts', 'basext_bookings_query' );

search for dates in bottom left corner Check-In Date: 12-12-2014 Check-out Date: 1-31-2015