I am modifying a site that currently has various custom post types. The structure of one to many relationships is basically

course
    lesson

lesson
    topic

lesson
    quiz

topic
    quiz

There are times when I want to get all quizzes associated with a lesson.

Currently the site uses individual queries to extract related data only between 2 post types.

For instance, to get quizzes for a lesson you have

$args = ['post_type' => 'sfwd-quiz',
         'numberposts' => -1,
         'orderby' => 'menu_order',
         'meta_key' => 'lesson_id',
         'meta_value' => get_the_id(),
         'meta_compare' => '='];

$quizzes = get_posts($args);

Now, I would prefer at times to retrieve all quizzes for a lesson, which means quizzes for a topic in a lesson, since a topic is tied to a lesson as many to one.

So is there a way to chain relationships in get_posts() meta data queries?

Something that syntactically would be

$quizzes = get_posts(where post type is quiz and meta_lesson_id = $id, OR where post type is quiz and meta_topic_id is related to lesson with meta_lesson_id = $id)

Thanks,
Brian

--------------------------------------------------

>>> Share a link to this question, just copy and paste the code bellow on your web page <<<

<a href="https://www.wptricks.com/question/using-meta-data-to-retrieve-related-posts-a-way-to-use-nested-relations/">

Using meta data to retrieve related posts - a way to use nested relations?</a>