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我在WordPress后台某篇文章的编辑页面,给这篇文章选择了分类:WordPress,接着同时选择了标签:php、主题制作,这时分类(WordPress)就与标签(php、主题制作)建立了关联,利用这种关联我们实现很多种需求,最典型的是细化WordPress文章分类功能,在子分类无法达到我们的需求时,可以使用标签来细化。我只需要提供WordPress分类的id,就可以得到它关联的标签:php、主题制作。 调用函数我们可以先在主题目录的下的functions.php添加以下函数: - function morko_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;
- }
复制代码 函数用法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
- $tags = morko_get_category_tags($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 $content;
复制代码好了,基本用法就这些,具体其他用法你可以自由地进行扩展。 获取某个标签关联的分类反过来,我们可能会有这样的需求,既然可以获取某个分类的关联标签,那我能获取某个标签的关联分类吗?答案是可以的,将上面的代码稍微改一下就可以了: - function morko_get_tag_categories($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;
- }
复制代码 调用范例- // 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
- $categories = morko_get_tag_categories($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;
复制代码
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