MySql select

Why this select doesn't work?

SELECT SUM( price ) AS vendita, MONTH( `offer_date` ) AS mese
FROM crm_module_offer, crm_module_offer_article
WHERE `id_project` =2
AND `status` = "WON"
AND crm_module_offer.id = crm_module_offer_article.id_offer
GROUP BY mese
LIMIT 0 , 30

phpMyAdmin returns 2 records (watch image 1), in Google Spreadsheet returns no records.