Nieznana kolumna mysql i losowanie stringa.

DELIMITER $$
CREATE PROCEDURE proc_pelnoletni()
BEGIN
    DECLARE s INT DEFAULT 0;
    etykieta3:LOOP
	UPDATE pracownicy 
	  SET pracownicy.pesel = (Select aa from(Select pesel as aa from ludzie where left(ludzie.pesel,1)<=9 and left(ludzie.pesel,2)<=9 order by rand() Limit 1) as A);
      SET s = s+1;
      IF s>=175 
      THEN LEAVE etykieta3; 
      END IF ;
      END LOOP;
      END $$
DELIMITER $$
call proc_pelnoletni();

select * from peoples;
+----+-------------+
| id | pesel       |
+----+-------------+
|  1 | 18395858492 |
|  2 | 18395123492 |
|  3 | 15855648391 |
|  4 | 29123459857 |
|  5 | 19123229857 |
+----+-------------+

delimiter //

create function sum1(number_as_str char(11), quantity int)
returns int deterministic
begin

declare i int default 1;
declare collect int default 0;

while i <= quantity do
	
	set collect = collect + cast(substring(number_as_str,i,1) as unsigned);
	
	set i = i + 1;
end while;

return collect;

end;//

select x, z, id, pesel from (select cast(sum1(left(peoples.pesel,2), 2) as unsigned) as x, cast(left(peoples.pesel,1) as unsigned) as z, id, pesel from peoples) as y where x<=9 and z<=9;

+------+------+----+-------------+
| x    | z    | id | pesel       |
+------+------+----+-------------+
|    9 |    1 |  1 | 18395858492 |
|    9 |    1 |  2 | 18395123492 |
|    6 |    1 |  3 | 15855648391 |
+------+------+----+-------------+

delimiter //
create procedure proc_adult()
begin
	declare s int default 0;
	label3: LOOP
		update trees3 
		set trees3.kind = (SELECT pesel FROM (SELECT CAST(sum1(LEFT(peoples.pesel,2), 2) AS UNSIGNED) AS x, CAST(LEFT(peoples.pesel,1) AS UNSIGNED) AS z, pesel FROM peoples)
		AS y WHERE x<=9 AND z<=9 order by rand() limit 1);
		
		if s > (select count(*) from trees3) then 
			leave label3;
		end if;
		set s = s + 1;
	end loop;
end//

delimiter ;

call proc_adult();