posti_esauriti
$meta_query = array( 'relation' => 'AND', array( 'key' => 'posti_esauriti', 'value' => '90', 'compare' => '<', 'type' => 'NUMERIC', ), );
$meta_query = array( 'relation' => 'AND', array( 'key' => 'posti_esauriti', 'value' => '90', 'compare' => '<', 'type' => 'NUMERIC', ), );