SELECT `p1`.`entity_id`
FROM `products` AS `p1`
JOIN `products` AS `p2` USING(`entity_id`)
WHERE `p1`.`value_id` = '19'
AND `p2`.`value_id` = '12'
SELECT `prod`.`name`, `prod`.`price`,
GROUP_CONCAT(CONCAT(`atr`.`nameAttribute`, '=' , `val`.`attributeValue`) as `attribute`,
FROM `products` as `prod`
LEFT JOIN `productAttribute` as `atr` ON `prod`.`idProduct` = `atr`.`idProduct`
LEFT JOIN `attributeValue` as `val` ON `atr`.`idAttribute` = `val`.`idAttribute`
WHERE `prod`.`idCategory` = :idCategory
GROUP BY `prod`.`idProduct`;
