Group by collection_item_id and order by products.weight

Question

SELECT 
    `products`.* 
FROM `products` 
    INNER JOIN collection_items ON products.collection_item_id = collection_items.id 
        WHERE `products`.`product_type_id` = 1 
AND (products.status = 'live') 
AND (products.belongs_to_sv = true) 
ORDER BY products.weight DESC

I am trying to get the record set ordered by products.weight but with only unique values for products.collection_item_id.

When I try to group, the ORDER BY isn't obeyed.