update using for loop in plsql

Question

i\'m having problem updating and insert into below column. Please advise on this.

This is the input

depnto   extra    comm
--------------------------         


        

Answer 1

 BEGIN
      FOR person IN (SELECT A   FROM EMP WHERE B IN (SELECT B FROM ustom.cfd_180518) )
     LOOP
        --dbms_output.put_line(person.A);
        UPDATE custom.cfd_180518 SET c = person.a;
      END LOOP;
 END;