Yoast SEO将主要术语ID存储为post meta字段_yoast_wpseo_primary_{taxonomy}. 知道了这一点，您可以使用元查询来获取具有主类别ID的所有帖子X:

$query = new WP_Query([
    \'cat\' => \'X\', // Just in case Yoast data corrupted & post no longer attached to X term but primary meta remains
    \'meta_query\' => [
        [
            \'key\' => \'_yoast_wpseo_primary_category\',
            \'value\' => \'X\',
        ]
    ],
]);