stored procedure, accessing data that has just been inserted - postgresql

Question

I am trying to insert values into a table based upon a person being inserted into another table. I have a trigger for this, when someone is assigned to employee, they are automatically assigned to employeepark with the first spot that is available. I cannot figure out how to access the id that is being input into the employee table. I would appreciate any tips or ideas, thank you !
This is the error I am receiving.
ERROR: record "new" is not assigned yet
create or replace function new_employeeAssign() returns trigger as $new_employeeAssign$
declare
open_spotID int := (select parkingspot.spotid
from employeepark e full outer join parkingspot on e.spotid = parkingspot.spotid
where e.spotid isNull limit 1);
begin
insert into employeepark(employeeid, spotid)
values(new.employeeid ,open_spotID);
End;
$new_employeeAssign$ language plpgsql;
create trigger new_employeeAssign after insert on employee
execute procedure new_employeeAssign();
insert into people(peopleid, fname, lname)
values(686, 'random', 'person');
insert into employee(employeeid)
values(686);
Patrick figured this out for me now I am running into THIS PROBLEM:
I want to select the first value out of all of these ranges that is null, I keep getting back one though and it is just bypassing the ranges and going straight to the isNull.
(select parkingspot.spotid
from employeepark e full outer join parkingspot on e.spotid = parkingspot.spotid
where (e.spotid = 301)
or (e.spotid = 1601)
or (e.spotid = 2001)
or (e.spotid = 2011)
or (e.spotid = 2121)
or (e.spotid = 2021)
or (e.spotid = 2771)
or (e.spotid = 2921)
or (e.spotid = 3021)
or (e.spotid = 3823) isNull
limit 1)

Answer 1

Your trigger definition is incorrect. By default, a trigger applies to FOR EACH STATEMENT and then the NEW parameter does not exist (the trigger does not apply to a row, after all). Instead you should have:
CREATE TRIGGER new_employeeAssign AFTER INSERT ON employee
FOR EACH ROW EXECUTE PROCEDURE new_employeeAssign();
There are also some issues with your trigger function, in particular the query that assigns to variable open_spotID. This query will always select NULL because e.spotid IS NULL and you join on e.spotid = parkingspot.spotid. The logic that you are looking for is probably that you want to assign a parking slot to a new employee by making a row in table employeepark with a spot_id that is not already assigned to some other employee. See code below.
You also have to RETURN NEW from the function.
Other than that, your trigger function could be much optimized like so:
CREATE FUNCTION new_employeeAssign() RETURNS trigger AS $new_employeeAssign$
BEGIN
INSERT INTO employeepark(employeeid, spotid)
SELECT NEW.employeeid, spotid
FROM parkingspot p
LEFT JOIN employeepark e USING (spotid)
WHERE e.employeeid IS NULL
LIMIT 1;
RETURN NEW;
END;
$new_employeeAssign$ LANGUAGE plpgsql;