SHOW when TAX not exists
$tax_query = array( 'relation' => 'AND', array( 'taxonomy' => 'zahlung', 'field' => 'name', 'operator' => 'NOT EXISTS', 'include_children' => true, ), );
$tax_query = array( 'relation' => 'AND', array( 'taxonomy' => 'zahlung', 'field' => 'name', 'operator' => 'NOT EXISTS', 'include_children' => true, ), );