[GENERAL] How to auto-increment?

[Andre Lopes]

Hi,

I have a table like this:

id_product
id_increment

and I need to increment values in id_increment like this

prod_1
1

prod_1
2

prod_1
3

prod_2
1

Wich is the best way to do this? Using a trigger? Where can I find examples
of plpgsql doing this?

Best Regards, André.

Sorry for my bad english.