Need to assign a discount scheme to a large number of items

Hello,

I am trying to assign a discount scheme to our clothing department 500+ items, need to have pricing discounted buy 1 item get 10% off, but 2 items get 20% off both and 3 items get 30% off all 3.  Setting this in the database can be accomplished 1 item at a time but this is very time consuming.  Is there a query to make this happen faster?