Question

I want to create a function which returns how many levels the boss is above the person(calling the function).

Here is the way i would like to do it, but i don’t quite know how SQL syntax works
http://pastebin.com/dyDaGwf9

the table looks like this:

workerid    name    chefid
1           Bob     
2           Alice   1
3           Joe     1
4           John    2
5           Dirk    4
6           Ralf    2
7           Lisa    1
8           Lyn     3

the final result upon calling the function should look like this

function call:

Select workerid, name, rankFunction(workerid) from workers;

workerid    name    rank
1           Bob     0
2           Alice   1
3           Joe     1
4           John    2
5           Dirk    3
6           Ralf    2
7           Lisa    1
8           Lyn     2

Would be great if somebody could shed some light,

Thanks!

Answer 1

Here you are, a simple recursion:

CREATE OR REPLACE FUNCTION rankFunction(worker_id int)
  RETURNS int AS
$BODY$
DECLARE
    temp_chefid int;
BEGIN
    temp_chefid := (SELECT chefid from workers where workerid = worker_id);
    IF(temp_chefid IS NULL) THEN
         RETURN 0;
    ELSE RETURN 1 + rankFunction(temp_chefid);
    END IF;
END;
$BODY$
  LANGUAGE plpgsql VOLATILE