我写了一个WP\\u查询，其行为很奇怪。我几乎什么都试过了，但都没用。我找到了一个解决方案，但我试着去理解。

以下查询始终返回来自第一个caregory（id:15，slug:slug1）的帖子。

$args = array(
    \'post_type\' => \'post\',
    \'post_status\' => \'publish\',
    \'category__in\'    => array(15, 17),
    \'posts_per_page\' => 4
);

$query = new WP_Query($args);
$items = $query->get_posts();

或

$args = array(
    \'post_type\' => \'post\',
    \'post_status\' => \'publish\',
    \'cat\'    => \'15,17\',
    \'posts_per_page\' => 4,
);

$query = new WP_Query($args);
$items = $query->get_posts();

或

$args = array(
    \'post_type\' => \'post\',
    \'post_status\' => \'publish\',
    \'category_name\'    => \'slug1,slug2\',
    \'posts_per_page\' => 4,
);

$query = new WP_Query($args);
$items = $query->get_posts();

或

$args = array(
    \'post_type\' => \'post\',
    \'post_status\' => \'publish\',
    \'posts_per_page\' => 4,
    \'tax_query\' => array(
        array(
            \'taxonomy\' => \'category\',
            \'field\'    => \'term_id\',
            \'terms\'    => array(15,17),
        ),
    ),
);

$query = new WP_Query($args);
$items = $query->get_posts();

解决方案是使用query\\u post（$args）而不是WP\\u query->get\\u posts（）

$args = array(
    \'post_type\' => \'post\',
    \'post_status\' => \'publish\',
    \'category__in\'    => array(15, 17),
    \'posts_per_page\' => 4
);

$items = get_posts($args);

你能告诉我哪里错了吗？

$args = array(
    \'post_type\' => \'post\',
    \'post_status\' => \'publish\',
    \'category__in\'    => array(15, 17),
    \'posts_per_page\' => 4
);

$query = new WP_Query();
$items = $query->query($args);