WordPress进行二次开发的时候，需要调用WordPress网站某个分类下文章的关联标签，也就是该分类下各文章使用过的标签，今天就为大家分享一下WordPress调用分类关联的标签或者标签关联的分类方法。

实现代码：

在当前主题的functions.php文件中添加以下函数代码：

function ludou_get_category_tags($args) {

global $wpdb;

$tags = $wpdb->get_results

(“

SELECT DISTINCT terms2.term_id as tag_id, terms2.name as tag_name

FROM

$wpdb->posts as p1

LEFT JOIN $wpdb->term_relationships as r1 ON p1.ID = r1.object_ID

LEFT JOIN $wpdb->term_taxonomy as t1 ON r1.term_taxonomy_id = t1.term_taxonomy_id

LEFT JOIN $wpdb->terms as terms1 ON t1.term_id = terms1.term_id,

$wpdb->posts as p2

LEFT JOIN $wpdb->term_relationships as r2 ON p2.ID = r2.object_ID

LEFT JOIN $wpdb->term_taxonomy as t2 ON r2.term_taxonomy_id = t2.term_taxonomy_id

LEFT JOIN $wpdb->terms as terms2 ON t2.term_id = terms2.term_id

WHERE

t1.taxonomy = ‘category’ AND p1.post_status = ‘publish’ AND terms1.term_id IN (“.$args[‘categories’].”) AND

t2.taxonomy = ‘post_tag’ AND p2.post_status = ‘publish’

AND p1.ID = p2.ID

ORDER by tag_name

“);

$count = 0;

if($tags) {

foreach ($tags as $tag) {

$mytag[$count] = get_term_by(‘id’, $tag->tag_id, ‘post_tag’);

$count++;

}

}

else {

$mytag = NULL;

}

return $mytag;

}

然后在其他主题文件中，我们可以调用某个分类或某几个分类关联的标签：

// 12,13是分类ID，多个用半角逗号隔开

$args = array( ‘categories’ => ‘12,13’);

// 调用上面定义的函数，来获取ID为12，13的分类的关联标签

$tags = ludou_get_category_tags($args);

// 输出我们获取到的关联标签，以列表形式打印

$content .= “<ul>”;

if(!empty($tags)) {

foreach ($tags as $tag) {

$content .= “<li><a href=”.get_tag_link($tag->term_id).””>”.$tag->name.”</a></li>”;

}

}

$content .= “</ul>”;

echo $content;

好了，基本用法就这些，具体其他用法你可以自由地进行扩展。

获取某个标签关联的分类

反过来，我们可能会有这样的需求，既然可以获取某个分类的关联标签，那我能获取某个标签的关联分类吗？答案是可以的，将上面的代码稍微改一下就可以了，在当前主题的functions.php文件中添加以下函数代码：

function ludou_get_tag_categories($args) {

global $wpdb;

$categories = $wpdb->get_results

(“

SELECT DISTINCT terms1.term_id as cat_id

FROM

$wpdb->posts as p1

LEFT JOIN $wpdb->term_relationships as r1 ON p1.ID = r1.object_ID

LEFT JOIN $wpdb->term_taxonomy as t1 ON r1.term_taxonomy_id = t1.term_taxonomy_id

LEFT JOIN $wpdb->terms as terms1 ON t1.term_id = terms1.term_id,

$wpdb->posts as p2

LEFT JOIN $wpdb->term_relationships as r2 ON p2.ID = r2.object_ID

LEFT JOIN $wpdb->term_taxonomy as t2 ON r2.term_taxonomy_id = t2.term_taxonomy_id

LEFT JOIN $wpdb->terms as terms2 ON t2.term_id = terms2.term_id

WHERE

t1.taxonomy = ‘category’ AND p1.post_status = ‘publish’ AND terms2.term_id IN (“.$args[‘tags’].”) AND

t2.taxonomy = ‘post_tag’ AND p2.post_status = ‘publish’

AND p1.ID = p2.ID

ORDER by cat_id

“);

$count = 0;

if($categories) {

foreach ($categories as $category) {

$mycategory[$count] = get_term_by(‘id’, $category->cat_id, ‘category’);

$count++;

}

}

else {

$mycategory = NULL;

}

return $mycategory;

}

调用范例：添加多个标签ID就调用多个标签的关联的分类

// 12,13是标签ID，多个用半角逗号隔开

$args = array( ‘tags’ => ‘12,13’);

// 调用上面定义的函数，来获取ID为12，13的标签的关联分类

$categories = ludou_get_tag_categories($args);

// 输出我们获取到的关联分类，以列表形式打印

$content .= “<ul>”;

if(!empty($categories)) {

foreach ($categories as $category) {

$content .= “<li><a href=”.get_category_link( $category->term_id ).””>”.$category->name.”</a></li>”;

}

}

$content .= “</ul>”;

echo $content;