DECLARE
l_deptno NUMBER:=10;
l_count NUMBER;
l_ename varchar2(20);
BEGIN
SELECT count(*) OVER(order by empno) ,ename INTO l_count,l_ename FROM emp WHERE ROWNUM=1 and deptno=l_deptno;
dbms_output.put_line(l_count||' '||l_ename);
end;

SQL> select ename, deptno, count(*) over (partition by deptno) nb
  2  from emp;
ENAME          DEPTNO         NB
---------- ---------- ----------
CLARK              10          3
KING               10          3
MILLER             10          3
JONES              20          5
FORD               20          5
ADAMS              20          5
SMITH              20          5
SCOTT              20          5
WARD               30          6
TURNER             30          6
ALLEN              30          6
JAMES              30          6
BLAKE              30          6
MARTIN             30          6

SELECT count(*), min(ename) FROM emp