woothemes / sensei

     * @param $user_id

     * @return double

     */

    public static function get_user_graded_lessons_sum( $user_id ){

        global $wpdb;

        $clean_user_id = esc_sql( $user_id);

        $comment_query_piece[ 'select']  = "SELECT SUM({$wpdb->commentmeta}.meta_value) AS meta_sum";

        $comment_query_piece[ 'from']    = " FROM {$wpdb->comments}  INNER JOIN {$wpdb->commentmeta}  ON ( {$wpdb->comments}.comment_ID = {$wpdb->commentmeta}.comment_id ) ";

        $comment_query_piece[ 'where']   = " WHERE {$wpdb->comments}.comment_type IN ('sensei_lesson_status') AND ( wp_commentmeta.meta_key = 'grade') AND {$wpdb->comments}.user_id = {$clean_user_id} ";

        $comment_query_piece[ 'orderby'] = " ORDER BY {$wpdb->comments}.comment_date_gmt DESC ";

        $comment_query = $comment_query_piece['select'] . $comment_query_piece['from'] . $comment_query_piece['where'] . $comment_query_piece['orderby'];

        $sum_of_all_grades = intval( $wpdb->get_var( $comment_query, 0, 0 ) );

        return $sum_of_all_grades;

    }

    /**

     * Get the sum of all user grades for the given lesson.

     * @param int lesson_id

     * @return double

     */

    public static function get_lessons_users_grades_sum( $lesson_id ){

        global $wpdb;

        $clean_lesson_id = esc_sql( $lesson_id);

        $comment_query_piece[ 'select']  = "SELECT SUM({$wpdb->commentmeta}.meta_value) AS meta_sum";

        $comment_query_piece[ 'from']    = " FROM {$wpdb->comments}  INNER JOIN {$wpdb->commentmeta}  ON ( {$wpdb->comments}.comment_ID = {$wpdb->commentmeta}.comment_id ) ";

        $comment_query_piece[ 'where']   = " WHERE {$wpdb->comments}.comment_type IN ('sensei_lesson_status') AND ( wp_commentmeta.meta_key = 'grade') AND {$wpdb->comments}.comment_post_ID = {$clean_lesson_id} ";

        $comment_query_piece[ 'orderby'] = " ORDER BY {$wpdb->comments}.comment_date_gmt DESC ";

        $comment_query = $comment_query_piece['select'] . $comment_query_piece['from'] . $comment_query_piece['where'] . $comment_query_piece['orderby'];

        $sum_of_all_grades = intval( $wpdb->get_var( $comment_query, 0, 0 ) );

        return $sum_of_all_grades;

    }//get_lessons_user_grades_sum

    /**

     * Get the sum of all user grades for the given course.

     * @param int $course_id

     * @return double

     */

    public static function get_course_users_grades_sum( $course_id ){

        global $wpdb;

        $clean_course_id = esc_sql( $course_id);

        $comment_query_piece[ 'select']  = "SELECT SUM({$wpdb->commentmeta}.meta_value) AS meta_sum";

        $comment_query_piece[ 'from']    = " FROM {$wpdb->comments}  INNER JOIN {$wpdb->commentmeta}  ON ( {$wpdb->comments}.comment_ID = {$wpdb->commentmeta}.comment_id ) ";

        $comment_query_piece[ 'where']   = " WHERE {$wpdb->comments}.comment_type IN ('sensei_course_status') AND ( wp_commentmeta.meta_key = 'percent') AND {$wpdb->comments}.comment_post_ID = {$clean_course_id} ";

        $comment_query_piece[ 'orderby'] = " ORDER BY {$wpdb->comments}.comment_date_gmt DESC ";

        $comment_query = $comment_query_piece['select'] . $comment_query_piece['from'] . $comment_query_piece['where'] . $comment_query_piece['orderby'];

        $sum_of_all_grades = intval( $wpdb->get_var( $comment_query, 0, 0 ) );

        return $sum_of_all_grades;

    }//get_lessons_user_grades_sum

} // End Class