SELECT TOP 1 Item.title, Item.description, Item.current_price, Item.picture, Item.increment, Item.seller_id, Category.category_name, Category.category_id 
FROM 
(
  Item INNER JOIN Category 
  ON Item.category_id = Category.category_id) 
  WHERE (Item.category_id IN 
  (
    SELECT favourite_category_id 
    FROM [User] 
    WHERE (username = ?)
  )
) 
ORDER BY Rnd(Item.item_id)