append on insert

[Kevin Waterson]

I have a table of item
I wish to have the value of the item incremented if there is a duplicate.
I looked at ON DUPLICATE KEY UPDATE but this modifies the exsisting value.
If the item is my-item and this already exists, I need to make it my-item-2
or even my-item-123 where 123 is the key.

Kind regards
Kevin