在过去的几个小时里，我一直在尝试使用过滤器挂钩posts_where 和posts_join 要根据分类法术语搜索帖子，在本例中，分类法为“category”，术语为“politics”

这是我尝试的结果，结果是一个空查询：

这条线在钩子里posts_where

$where .= " OR ($wpdb->term_taxonomy.taxonomy IN (\'category\') AND $wpdb->terms.name = \'politics\')";

这就是我用来连接不同表的方法：

$join .= " LEFT JOIN $wpdb->postmeta ON $wpdb->posts.ID = $wpdb->postmeta.post_id ";
$join .= " LEFT JOIN $wpdb->term_relationships ON ($wpdb->posts.ID = $wpdb->term_relationships.object_id) ";
$join .= " LEFT JOIN $wpdb->term_taxonomy ON ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id) ";
$join .= " LEFT JOIN $wpdb->terms ON($wpdb->term_taxonomy.term_id = $wpdb->terms.term_id) ";

我确实想出了一个可行的替代方案，但我想知道我在前面的代码中犯了什么错误，以及如何使其工作。

可行的替代方案是这样的（不使用posts_join 挂钩）：

$search .= " OR ($wpdb->posts.ID IN( 
    SELECT $wpdb->term_relationships.object_id as post_id 
    FROM $wpdb->term_taxonomy,  $wpdb->terms, $wpdb->term_relationships 
    WHERE $wpdb->term_taxonomy.term_id =  $wpdb->terms.term_id
    AND $wpdb->term_relationships.term_taxonomy_id =  $wpdb->term_taxonomy.term_taxonomy_id
    AND $wpdb->term_taxonomy.taxonomy in (\'category\')
    AND ($wpdb->terms.name LIKE \'politics\')  
    )
)";

那么，我如何使用posts_where 和posts_join 查询分类术语的挂钩？

$where .= " OR ($wpdb->term_taxonomy.taxonomy IN (\'category\') AND $wpdb->terms.name LIKE \'politics\')";

$where .= " OR ( taxonomy IN (\'category\') AND name LIKE \'politics\')";

$where .= " OR (wtt.taxonomy IN (\'category\') AND wt.name LIKE \'politics\' )";

$join .= " LEFT JOIN $wpdb->term_relationships as wtr ON ($wpdb->posts.ID = wtr.object_id) ";
$join .= " LEFT JOIN $wpdb->term_taxonomy as wtt ON (wtr.term_taxonomy_id = wtt.term_taxonomy_id) ";
$join .= " LEFT JOIN $wpdb->terms as wt ON(wtt.term_id = wt.term_id) ";