CREATE TABLE job_cnt (cnt NUMBER,JOB VARCHAR2(10));

DECLARE
  l_pre_val VARCHAR2(100):='1';
  l_cur_val VARCHAR2(100):='1';
  l_cnt     NUMBER       :=0;
BEGIN
  FOR i IN
  (SELECT JOB FROM emp ORDER BY 1 )
  LOOP
    l_cur_val   :=i.JOB;
    IF l_pre_val<>l_cur_val THEN
      l_cnt     :=1;
      dbms_output.put_line('insert'||l_cnt||' '||l_cur_val);
      INSERT INTO job_cnt VALUES(l_cnt,l_cur_val );
    ELSE
      l_cnt :=l_cnt+ 1;
      dbms_output.put_line('update'||l_cnt||' '||l_cur_val);
      UPDATE job_cnt SET cnt=l_cnt WHERE job=l_cur_val;
    END IF;
    l_pre_val:=l_cur_val;
  END LOOP;
  COMMIT;
END;

SELECT * FROM job_cnt;