master/detail

Hi,

I'm trying to get my head around the following question. As an example
take a table with products:

productid (pk)
name

and productprice

productpriceid (pk)
productid (fk)
pricedate
price

There are multiple records in productprice for each product as prices
(often) go up and (less often) go down.

I'm looking for a query that returns the following:

productid, name, pricedate, current_price, difference

current_price is the latest (ie. most recent date) price of the product
and difference is the difference in price between the latest price and
the price before the latest.

Any suggestions how to do this with SQL only? I can make it work with a
function (probably less efficient) but think this should be possible
with SQL too...

cheers,
Jan