我有两种自定义帖子类型：Books 和Subjects. 对于此项目，我使用Super CPT创建自定义帖子类型：

$books = new Super_Custom_Post_Type( \'book\', \'\', \'book\', $register = array(
        \'supports\' => array( \'title\', \'editor\', \'thumbnail\'),
        )
);

$subjects= new Super_Custom_Post_Type( \'subject\', \'\', \'\', $register = array(
        \'supports\' => array( \'title\', \'editor\'),
        \'hierarchical\' => true,
        ) 
);

为了选择本书的主题，我创建了一个元框和来自主题的值：

$profissionais->add_meta_box( array(
        \'id\' => \'subjects\',
        \'context\' => \'side\',
        \'fields\' => array(
              \'subjects\' => array( \'type\' => \'select\', \'label\' => \'\', \'data\' => \'subject\', \'multiple\' => \'multiple\' )
        )
) );

现在，我需要在每个主题的页面上显示与此主题相关的书籍。我从以下内容开始：

$args = array(
  \'post_type\' => \'book\',
);
$books = new WP_Query($args);

但我不知道如何前进。我正在尝试这样做：

SELECT book_title FROM books WHERE subject = subject page title

UPDATE

已解决！

$current = get_the_ID();

 $args = array(
   \'post_type\' => \'book\',
   \'posts_per_page\' => -1,
   \'meta_key\' => \'subjects\',
   \'meta_value\' => $current,
 );

 $books = new WP_Query($args);

$args = array(
    \'post_type\' => \'book\',
    \'posts_per_page\' => -1,
    \'meta_key\' => \'subject\',
    \'meta_value\' => YOUR_SUBJECT_PAGE_TITLE,
);
$books = new WP_Query($args);