Get all posts grouped by term

helpers.php

/**
 * Gets all of the posts grouped by terms for the specified
 * post type and taxonomy.
 *
 * Results are grouped by terms and ordered by the term and post IDs.
 *
 * @since 1.0.0
 *
 * @param string $post_type_name Post type to limit query to
 * @param string $taxonomy_name Taxonomy to limit query to
 *
 * @return array|false
 */
function get_posts_grouped_by_term_from_db( $post_type_name, $taxonomy_name ) {
	global $wpdb;
	$sql_query =
		"SELECT t.term_id, t.name AS term_name, t.slug AS term_slug, p.ID AS post_id, p.post_title
FROM {$wpdb->term_taxonomy} AS tt
INNER JOIN {$wpdb->terms} AS t ON (tt.term_id = t.term_id)
INNER JOIN {$wpdb->term_relationships} AS tr ON (tt.term_taxonomy_id = tr.term_taxonomy_id)
INNER JOIN {$wpdb->posts} AS p ON (tr.object_id = p.ID)
WHERE p.post_status = 'publish' AND p.post_type = %s AND tt.taxonomy = %s
GROUP BY t.term_id, p.ID
ORDER BY t.term_id, p.ID ASC;";
	$sql_query = $wpdb->prepare( $sql_query, $post_type_name, $taxonomy_name );
	$results = $wpdb->get_results( $sql_query );
	if ( ! $results || ! is_array( $results ) ) {
		return false;
	}
	return $results;
}