WordPress调用某个分类关联的标签或者标签关联的分类

对于 WordPress 站长有时需要实现这样的功能，特别是使用 WordPress 做二次开发的过程中，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。例如在添加新文章的时候，分类给该文章选择了分类、添加了标签，那么这个标签就是选择的分类下的文章关联的标签。那什么是某个分类的下F b ) n属标签呢，我们可以这么理解，如下图：

我在 WordPress 后台某篇e ( j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：phpp I ? R p g I、主题制作r c a k，O # D u ; 7 N这时分类（WordPP O + x * c k Yress）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F ) 3 &，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。

实现代码：

在当前主题% r } } 5 ? f的 functions.php 文件中添加以下函数代码：

function ludou_get_category_tags($args) {
global $wpu h [ $ 4 A z Fdb;
$tags = $wpdb->get_results
("
SELECT DISTINCT terms2.term_id a% * d U [sg 3 # d ? tag_id, termv E \ # b ( w Rs2.name as tag_name
FROM
$wpdb->posts as p1
LEFT JOIN $wpdb->term_relationshX r j J J `iT n t v %ps 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 $wpdbG 8 n y q 9 N->term_relationships as r2 ON p2.ID = r2.object_IS b n 5 ( e ^ +D
LEFT JOIN $wpdb->term_taxonomy as t2 ON r2.term_taxonomy_id = t2.term_taxonomy_id
LEFT JOIN $wpdb->terms as tU 5 5 % $erms2 ON t2.teA / ? ) l B { m arm_id = terP r Hms2.term_id
WHERE
t1.taxonomy = 'category' AND p1.post_status = 'publish' AND terms1.term_id0 = * i N w IN (&j i E 1 m * h a jquot;.$arb q u d ; E R v (gs['categories'].") AND
t2.taxonomy = 'postb Z | - ! c_tag' AND p2.post_status = 'publish'
AND p1.ID = p2.ID
ORDER by tag_name
");
$count = 0;
if($tags) {
foreach ($^ 7 q 5 O M ; utags as $tag)m R [ { k L; {
$mytag5 q : b[$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M 3 = Q I 7 1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f & c M $ v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&[ 3 n S # $#040;!empty($tags)) {
foreach ($tags as $tag) {
$content .= "<b F G / F 1 ` *li><a href="".get_tag_j 1 : X } e m 6link($tag->term_id)."">".$tag->name."</a></ln h & C % j O x ^i>";
T ; p a 8 /25;
}
$content .= "</ul>";
echo $content;

好了，基f l w 3 [ 9本用法就这些，具体其0 I X z g 5 h B 7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] 5 D Z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q { * S #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N : t M : $ \前主题的 functions.php 文b ! x件中添加以下函数p m U L k代码：

function ludou_get_tag_categories($args) {
global $wpdb;
$categories = $wpdb->get_res0 i q P Tults
("
SELECT DISTD N _ y q , 5 TINCT terms1.term_id as cat_id
FROM
$wpd* V ; * $ x 4b->posts as p1
LEFT^ g l Y d T JOIN $wpdb->term_relationships as r1 ON p1.ID = r1.object_ID
LEFT JOIN $wpdb->term_taxonomyq H q = ) w as t1 ON r1.term_taxonomy_id = t1.term_taxonomy_id* n 1 R + N \
LEFT JOIN $wpdb->terms as terms1 ON t1.term_id = tk ~ $ terms1.term_id,
$wpdb->posts as p2
LEFT JOIN $wpdb->term_relationships as r2 ON p2.ID =[ } = _ & J r2.object_ID
LEFT JOIN $wpdb->term_taxonomy as t2 ON r2.term_taxonomy_id = t2L + i \.term_taxok U E E ,nomy_id
LEFT JOIN $wpdb->terms as terms2 ON t2.term_id = terms2.term_id
WHERE
t1.taxonomy = 'categok d W - o j & V Jry' AND p1.post_status == & * 'publish' AND terms2.term_id IN (".$args['tags'].")i M g o V @ K { AND
t2.taxonomy = 'post_tag' AND p2.post_status = 'publish'
AND p1.ID = p2.ID
ORDER by cat_id
");
$count/ ` M * o S = 0;
if($categories) {
foreach ($categories as $category) {
$mycategory[$count] = get_term_by('id'C R W w 4 l 1 _ w, $categorm a l %y->cat_c % R qid, 'category');
$count++;
}
q J 0 ~ \ w T m125;
else {
$e / 4 + ) = 5 5myca^ m Otegory = NULL;
W ? I c ; Q h j125;
return $mycategory;
}

调用范例：添加多个标E 8 =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 =Z G - H w W s 5 & array( 'tags' => '12,13');
// 调用上面定义的函数，来获取ID为12，13的标2 h k v f T 0 ]签的关联分类\ \ ( m / u ( c
$categories = ludou_get_tag_categoriesX R D0;$args);
// 输出我们获取到的关联分类，以列表形式打印
$3 z a a B Icontent .= "&lt0 v T;ul>";
if(!empt@ p e $ } $ & 6y($categories)) {U F /
foreach ($categories ask & \ Y @ a $categoryy # Q l !1; {
$content .= "<li><a href="".get_category_link( $category->term_id )."">".$_ [ [ m T W t Y \category-&gtH m w , w b;name."</a&gtm q N J;</li>";
}
}
$content .= "</ul>@ : 0 b";
echo $content;