class SKU():
    pass

class EntitySKU():
    sku = ForeignKey(SKU)
    attribute = ForeignKey(Attribute)
    attributevalue = ForeignKey(AttributeValue)

class AttributeValue():
    value = CharField("Значение")
    my_order = IntegerField(default=0)

class Attribute():
    title = models.CharField("Название", max_length=255)
    my_order = IntegerField(default=0)

SELECT `product_sku`.`id`, `product_attribute`.`title`, `product_attributevalue`.`value`,
`product_attribute`.`my_order` AS attribute_order,
`product_attributevalue`.`my_order` AS attributevalue_order
FROM `product_sku` 
LEFT OUTER JOIN `product__entity_sku` ON (`product_sku`.`id` = `product__entity_sku`.`sku_id`) 
LEFT OUTER JOIN `product_attribute` ON (`product__entity_sku`.`attribute_id` = `product_attribute`.`id`) 
LEFT OUTER JOIN `product_attributevalue` ON (`product__entity_sku`.`value_id` = `product_attributevalue`.`id`) 
WHERE `product_sku`.`product_id` = 1 
ORDER BY `product_attribute`.`my_order` ASC, `product_attributevalue`.`my_order` ASC