For each value of PC speed that exceeds 600 MHz, define the average price of the PCs with identical speeds.

Result set: speed, average price.

TRY executing the following syntax.

select speed, avg(price) as AVG_PRICE from pc where speed>600 group by speed

Right.

The result of Your query:

speedAVG_PRICE

750900.0000

800970.0000

900980.0000