Re: query: last N price for each product?

David Garamond wrote:
> Dear SQL masters,
> 
> The query for "latest price for each product" goes like this (which I
> can grasp quite easily):
> 
>  SELECT * FROM price p1
>  WHERE ctime=(SELECT MAX(ctime) FROM price p2 WHERE p1.product_id=p2.product_id)
> 
> or:
> 
>  SELECT * FROM price p1
>  WHERE NOT EXISTS (SELECT * FROM price p2 WHERE
> p1.product_id=p2.product_id AND p1.ctime < p2.ctime)
> 
> but how do yo query for "latest 3 prices for each product"? The
> "price" table contains current price as well as price histories.


Is this what you are looking for...

SELECT * FROM price p1
WHERE ctime in (SELECT ctime FROM price p2 WHERE 
p1.product_id=p2.product_id ORDER BY ctime DESC LIMIT 3)