Question

I want to set a trigger that effects only the row that is inserted, not the other rows.

So I need something different than for each row. Here is what I have now.

CREATE TRIGGER mytrigger BEFORE INSERT ON student
FOR EACH ROW SET @starost =new.starost+2;

Answer 1

You nearly had it:

CREATE TRIGGER mytrigger BEFORE INSERT ON student 
FOR EACH ROW SET new.starost =new.starost+2;

It will add two to the starost field before insertion