UPDATE a value several times in same UPDATE

[Bigcrime Crimebig]

Hi!

I will explain my problem in one example:

UPDATE products SET amount = amount+1 WHERE clientid IN ('1','2','4','3','4','4');

as you can see clientid number 4 is repeated 3 times
but it will be updated 1 time only.

I want to tell mysql that update each clientid each time they appear.

How can I do ThaT?

Ill appreciate your help a lot!