Erro na consulta por id

Minha consulta de produtos só retorna 5 itens, sendo que existem centenas no banco. Segue a consulta:

SELECT product.id_product, product.reference, product.price, product.active, product.quantity, product.id_category_default, lang.name AS product_name, lang.description, lang.link_rewrite AS product_link_rewrite, category.name AS category_name, category.link_rewrite AS category_link_rewrite, image.id_image, product.id_manufacturer, discount.reduction, manufacturer.name AS manufacturer_name FROM ps_product product
LEFT JOIN ps_specific_price discount ON discount.id_product=product.id_product
LEFT JOIN ps_product_lang lang ON lang.id_product=product.id_product
LEFT JOIN ps_category_lang category ON category.id_category=product.id_category_default
LEFT JOIN ps_image image ON image.id_product=product.id_product
LEFT JOIN ps_manufacturer manufacturer ON manufacturer.id_manufacturer=product.id_manufacturer
WHERE product.active=1 AND product.quantity>=1 AND product.id_category_default IN (4,5,6,65,66,90,91,53,54,48,49,50,55,62,67,68,71,19,82,88,89,87,22,24,26,74,76,77,28,78,79,97,98,99,93,96,35,36,38,39,100)
GROUP BY product.id_product ASC

Alguém pode me indicar o erro? Obrigado desde ja.