SQL> set serveroutput on
SQL> ed
Wrote file afiedt.buf

  1  declare
  2   v_peremennaja varchar2(20) :='CLERK';
  3   v_cc pls_integer :=0;
  4  begin
  5   --select count(*) from emp e where e.job=v_peremennaja;
  6   for r in (select job from emp e) loop
  7     if r.job=v_peremennaja then
  8       v_cc:=v_cc+1;
  9     end if;
 10   end loop;
 11   dbms_output.put_line(v_peremennaja||' к-во '||to_char(v_cc));
 12* end;
SQL> /
CLERK к-во 4

PL/SQL procedure successfully completed.

SQL> select ename,job from emp order by 2;

ENAME      JOB
---------- ---------
SCOTT      ANALYST
FORD       ANALYST
MILLER     CLERK
JAMES      CLERK
SMITH      CLERK
ADAMS      CLERK
BLAKE      MANAGER
JONES      MANAGER
CLARK      MANAGER
KING       PRESIDENT
TURNER     SALESMAN

ENAME      JOB
---------- ---------
MARTIN     SALESMAN
WARD       SALESMAN
ALLEN      SALESMAN