If statement

Hello everyone - newbie....
Is there a formula for something like this?
If cell A1 equals 0, then leave cell G2 blank AND
If cell A1 is greater than 0 then perform a calculation in g2 (B2-F2 is the formula)

I have this huge spreadsheet and I only want it to calculate the formula in G2 if there is a value in there.

Hope I make sense!