Jim,
I didn't see anyone mention the "mode" or most commonly occurring value, so I thought I would. It seems that it would also be useful in your business.
SELECT Price, COUNT(*) AS NumberSold ;
FROM Sales ;
GROUP BY 1 ;
ORDER BY 2 DESCENDING
YOu might never have sold a foal for the "average" price, but you sell most foals for the "mode" price.
>My boss wants to calculate the average and medium price for horses sold.
>What are the philosopical differences between the two methods?