MySQL Fatal Error

/home/apit/public_html/wax/wax_db.php at line 64

Wax method: customGet
Expression #1 of ORDER BY clause is not in SELECT list, references column 'apit_wax.scaffold_noticias.created_at' which is not in SELECT list; this is incompatible with DISTINCT

Query: SELECT DISTINCT(MONTH(created_at)) AS mes, YEAR(created_at) AS ano FROM scaffold_noticias ORDER BY created_at DESC