Question

I want to create a trigger, somehow like this:

CREATE TRIGGER foo 
AFTER UPDATE OR INSERT ON bar 
FOR EACH ROW EXECUTE PROCEDURE baz(NEW.id);

The part with NEW.id doesn’t work. How can I send values from the changed row (id for instance) to the trigger-function.

Answer 1

The trigger function (procedure) knows NEW and OLD automatically. No need to pass those as parameters.
Read more in the chapter on Trigger Procedures in the manual:

When a PL/pgSQL function is called as a trigger, several special
variables are created automatically in the top-level block. They are:

NEW

Data type RECORD; variable holding the new database row for INSERT/UPDATE operations in row-level triggers. This variable is NULL
in statement-level triggers and for DELETE operations.