Invoice number always the same as order id

[dhobo]

Hi,

 

On my shop I would like the invoice number to be the same as the order id associated with this invoice. First this worked perfectly, but as soon as I started cancelling orders before a payment was made, this got screwed up.

I have right now 146 orders in my shop - 144 "good" ones and 2 that I had to cancel. If I get a new order today, it will put the order id on 147, but the invoice number will be 145. Is there a way to always use the order id for the invoice number? I will definitely have to cancel orders in future as well, so constantly going back into the backoffice to manually change the starting order number is not the preferred option.

 

Is it possible to do this with either an override class, hooks or a mysql trigger?