> I'm new to triggers and I'm having difficulty in understanding how
> statement level triggers on before updates work.
> I have a function that sets new.last_modified := current_timestamp;
> If I were to define a trigger as:-
> CREATE TRIGGER my_trigger
> BEFORE INSERT OR UPDATE
> ON my_table
> FOR EACH STATEMENT
> EXECUTE PROCEDURE my_function();
> and my update statement were to update more than one row, would I be
> correct in understanding that every row the update statement touches
> will have the exact same value for last_modified?
No, this is not going to work at all. NEW and OLD are not available in
statement triggers. So your function will fail.