WordPress获取某个分类关联的标签
点水发表于 2014-07-09 05:38:19
在使用WordPress做二次开发的过程中，遇到这样的一个需求，如何获取某个分类下属的标签？那什么是某个分类的下属标签呢，我们可以这么理解，如下图：
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：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 | 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; } |
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：
1 2 3 4 5 6 7 8 9 10 11 12 13 | // 12,13是分类ID，多个用半角逗号隔开 $args = <a href="http://www.php.net/array">array</a>( '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 $content .= "<ul>"; if(!<a href="http://www.php.net/empty">empty</a>($tags)) { foreach ($tags as $tag) { $content .= "<li><a href=\"".get_tag_link($tag->term_id)."\">".$tag->name."</a></li>"; } } $content .= "</ul>"; echo $content; |
好了，基本用法就这些，具体其他用法你可以自由地进行扩展。
获取某个标签关联的分类
反过来，我们可能会有这样的需求，既然可以获取某个分类的关联标签，那我能获取某个标签的关联分类吗？答案是可以的，将上面的代码稍微改一下就可以了：
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 | function ludou_get_tag_categories($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：
1 2 3 4 5 6 7 8 9 10 11 12 13 | // 12,13是标签ID，多个用半角逗号隔开 $args = <a href="http://www.php.net/array">array</a>( '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 $content .= "<ul>"; if(!<a href="http://www.php.net/empty">empty</a>($categories)) { foreach ($categories as $category) { $content .= "<li><a href=\"".get_category_link( $category->term_id )."\">".$category->name."</a></li>"; } } $content .= "</ul>"; echo $content; |
文章来源于点水集，原文地址：http://www.dianshui.net/website/1768.html