首先，您需要hydro term的术语id，您可以使用get_term_by

$hydro = get_term_by(\'slug\', \'hydro\', \'product_cat\');

之后，您可以使用术语id作为\'parent\' 的参数get_terms

$hydro_children = get_terms( \'product_cat\', array( \'parent\' => $hydro->term_id ) );

现在，您可以显示这些子项的列表：

if ( ! empty($hydro_children) ) {
  echo \'<ul>\';
  foreach( $hydro_children as $hydro_child ) {
    echo \'<li><a href="\' . get_term_link($hydro_child, \'product_cat\') . \'">\';
    echo $hydro_child->name . \'</a></li>\';
  }
  echo \'</ul>\';
}

和/或使用$hydro_children 附加条款，如果需要，可以跳过只有$hydro_children 术语（“hydro”的孙子孙女），感谢\'include_children\' 税务查询参数：

$args = array(
  \'post_type\' => \'product\', // I guess
  \'tax_query\' => array(
    array(
      \'taxonomy\' => \'product_cat\',
      \'field\' => \'id\',
      \'terms\' => wp_list_pluck($hydro_children, \'term_id\'),
      \'include_children\' => false
    )
   )
);
$query = new WP_Query( $args );