Chaining Taxonomy Queries

Question

I have a quick question.

Could someone show me how to make a loop that does the following.

Query all posts for one tax (Meal Time: eg. Lunch, dinner, dessert...)

then

Loop each taxonomy (Courses: eg. apps, entrees, desserts...) and display all posts related to that tax.

then continue to loop through until there are no more related taxonomies the the parent "meal time" tax.

Answer 1

Use get_categories to return the terms in each taxonomy then loop through each getting the posts.

$args = array(
    'taxonomy' => 'meal_time'
);
$meal_times = get_categories( $args );
    foreach ( $meal_times as $meal ) {
            echo '<h3 class="meal-title">' . $meal->cat_name . '</h3>'; //Shows the term name as the title then loops through courses

        $child_args = array(
            'taxonomy' => 'courses'
        );

        $courses = get_categories( $args );
            foreach ( $courses as $course ); {

                echo '<h4 class="course-title">' .$course->cat_name. '</h4>'; //Shows the course then gets the posts

                $new_args = array(
                    'cat' => $meal->term_id,$course->term_id,
                    'posts_per_page' => -1
                );

                    $my_query = new WP_Query( $new_args );

                        while ( $my_query->have_posts () ) : $my_query->the_post ();

                        //Do stuff

                        endwhile;
            }

    }

This will return:

Lunch

- appetizers

All posts assigned with the Lunch Meal Time term and the Appetizers Course Term

- entrees

All posts assigned with the Lunch Meal Time term and the Entrees Course Term

Dinner

- appetizers

- entrees

etc...