search.php

<?php

$args = array(
    'posts_per_page'   => 5,
    'orderby'          => 'post_title',
    'order'            => 'ASC',
    'post_type'        => 'tour',
    'post_status'      => 'publish',
    'paged' => $paged
);

$sdate = !empty($_GET['sdate']) ? sanitize_text_field($_GET['sdate']) : 0;
     
if( '' != $sdate){
    $start_date = date('Ymd', strtotime($sdate));
    $args['meta_query'] = array(
      'key'	    => 'date_and_price_date', 
      'value'   => $start_date, 
      'compare'	=> '<=',
      'type'    => 'numeric',
    );
}
?>