Gentleman, I use Firebird 2.1,

I have two tables, BUYINGS and PRODUCTS

PRODUCTS
produ_averageprice numeric (15.1)

BUYINGS
buying_price numeric (15.1)


Well, I have bought one product 15 times, each cost price is different. So, I want field produ_averageprice get the average of the last 10 cost prices recorded in buying_price.
How do I make a select statement for this?

I think it's something like "select avg(select last 10 buying_price from BUYINGS)"

Were I clear? Please tell me if no, ok?

Thanks from Brazil,

Fabio.

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