wordpress获取指定分类下标签的方法

我们在进行wordpress主题开发或者wordpress二次开发过程中，在调用分类时，经常需要获取分类下的标签，现在就为大家介绍两种获取分类下标签的方法。
方法一：通过SQL获取（推荐）
将以下代码拷贝到你主题的functions.php中：

function get_category_tags($args) {
    global $wpdb;
    $tags = $wpdb->get_results
    ("
        SELECT DISTINCT terms2.term_id as tag_id, terms2.name as tag_name, null as tag_link
        FROM
            wp_posts as p1
            LEFT JOIN wp_term_relationships as r1 ON p1.ID = r1.object_ID
            LEFT JOIN wp_term_taxonomy as t1 ON r1.term_taxonomy_id = t1.term_taxonomy_id
            LEFT JOIN wp_terms as terms1 ON t1.term_id = terms1.term_id,
            wp_posts as p2
            LEFT JOIN wp_term_relationships as r2 ON p2.ID = r2.object_ID
            LEFT JOIN wp_term_taxonomy as t2 ON r2.term_taxonomy_id = t2.term_taxonomy_id
            LEFT JOIN wp_terms as terms2 ON t2.term_id = terms2.term_id
        WHERE
            t1.taxonomy = 'category' AND p1.post_status = 'publish' AND terms1.term_id IN (".$args['categories'].") AND
            t2.taxonomy = 'post_tag' AND p2.post_status = 'publish'
            AND p1.ID = p2.ID
        ORDER by tag_name
    ");
    $count = 0;
    foreach ($tags as $tag) {
        $tags[$count]->tag_link = get_tag_link($tag->tag_id);
        $count++;
    }
    return $tags;
}

然后你就可以在模板中使用这个函数了：

$args = array('categories' => '12,13,14'); //分类ID，根据自己需要调用不同的分类ID
$tags = get_category_tags($args);

方法二：通过query_post()函数

<?php
query_posts( array ( 'category_name' => 'my-category' ) );  //调用分类名为my-category,分类名根据自己需要修改
if (have_posts()) :
	$all_tags_arr=array(); 
	while (have_posts()) :
		the_post();
		$posttags = get_the_tags();
		if ($posttags) {
			foreach($posttags as $tag) {
			//print_r($all_tags_arr);
			if(in_array($tag->name,$all_tags_arr)){
			  continue;
			}else{
			 $all_tags_arr[] = $tag->name;
			echo “<a href =/?tag=”.$tag->name.”>”.$tag->name.”</a>”;
			 //print_r($tag); //输出tag
			}
		}
	}
	endwhile;
endif;?>