woothemes / sensei

		$id_list = join( ',', $lesson_ids );

		$meta_list = $wpdb->get_results( "SELECT post_id, meta_value FROM $wpdb->postmeta WHERE meta_key = '_quiz_lesson' AND meta_value IN ($id_list)", ARRAY_A );

		$lesson_quiz_ids = array();

		if ( !empty($meta_list) ) {

			foreach ( $meta_list as $metarow ) {

				$lesson_id = $metarow['meta_value'];

				$quiz_id = $metarow['post_id'];

				$lesson_quiz_ids[ $lesson_id ] = $quiz_id;

			}

		}

		// ...check all Quiz IDs for questions

		$id_list = join( ',', array_values($lesson_quiz_ids) );

		$id_list = join( ',', $lesson_ids_with_quizzes );

		$meta_list = $wpdb->get_results( "SELECT post_id, meta_value FROM $wpdb->postmeta WHERE meta_key = '_quiz_lesson' AND meta_value IN ($id_list)", ARRAY_A );

		$lesson_quiz_ids = array();

		if ( !empty($meta_list) ) {

			foreach ( $meta_list as $metarow ) {

				$lesson_id = $metarow['meta_value'];

				$quiz_id = $metarow['post_id'];

				$lesson_quiz_ids[ $lesson_id ] = $quiz_id;

			}

		}

		// ...get all Pass Required & Passmarks for the above Lesson/Quizzes

		$id_list = join( ',', array_values($lesson_quiz_ids) );

		// Get all Lesson => Course relationships

		$meta_list = $wpdb->get_results( "SELECT $wpdb->postmeta.post_id, $wpdb->postmeta.meta_value FROM $wpdb->postmeta INNER JOIN $wpdb->posts ON ($wpdb->posts.ID = $wpdb->postmeta.post_id) WHERE $wpdb->posts.post_type = 'lesson' AND $wpdb->postmeta.meta_key = '_lesson_course'", ARRAY_A );

		$course_lesson_ids = array();

		if ( !empty($meta_list) ) {

			foreach ( $meta_list as $metarow ) {

				$lesson_id = $metarow['post_id'];

				$course_id = $metarow['meta_value'];

				$course_lesson_ids[ $course_id ][] = $lesson_id;

			}

		}

		$users_sql = "SELECT ID FROM $wpdb->users ORDER BY ID ASC LIMIT %d OFFSET %d";

		$start_sql = "SELECT comment_post_ID, comment_date FROM $wpdb->comments WHERE comment_type = 'sensei_course_start' AND user_id = %d GROUP BY comment_post_ID ";

		// Get all Lesson => Course relationships

		$meta_list = $wpdb->get_results( "SELECT $wpdb->postmeta.post_id, $wpdb->postmeta.meta_value FROM $wpdb->postmeta INNER JOIN $wpdb->posts ON ($wpdb->posts.ID = $wpdb->postmeta.post_id) WHERE $wpdb->posts.post_type = 'lesson' AND $wpdb->postmeta.meta_key = '_lesson_course' LIMIT $n OFFSET $offset ", ARRAY_A );

		if ( !empty($meta_list) ) {

			foreach ( $meta_list as $metarow ) {

				$lesson_id = $metarow['post_id'];

				$course_id = $metarow['meta_value'];

				$course_lesson_ids[ $course_id ][] = $lesson_id;

			}

		}

		// Get all Lesson => Course relationships

		$status_list = $wpdb->get_results( "SELECT user_id, comment_post_ID, comment_approved FROM $wpdb->comments WHERE comment_type = 'sensei_lesson_status' GROUP BY user_id, comment_post_ID ", ARRAY_A );