Counter in a select

Question

Hi, I need a counter in a select without using temporal tables. Simplified, it's:
select a.code, b.desc
from a, b
where a.code=b.code
(table a has several fields as pk, not only 'code')
and results are:
coda Barcelona
codb New York
codc New York
codd Paris
and should be
coda Barcelona 1
codb New York 1
codc New York 2
codd Paris 1
Using group by and nested selects I get the total of lines by city (eg: Barcelona 1, New York 2,...), but not the number of line.
Thanks!

Answer 1

How about this?
SQL> r
  1  select dname, ename,
  2         row_number() over (partition by dname order by ename) rn
  3  from emp, dept
  4* where emp.deptno=dept.deptno
DNAME          ENAME              RN
ACCOUNTING     CLARK               1
ACCOUNTING     KING                2
ACCOUNTING     MILLER              3
RESEARCH       ADAMS               1
RESEARCH       FORD                2
RESEARCH       JONES               3
RESEARCH       SCOTT               4
RESEARCH       SMITH               5
RESEARCH       WARD                6
SALES          ALLEN               1
SALES          BLAKE               2
SALES          JAMES               3
SALES          MARTIN              4
SALES          TURNER              5
SALES          WARD                6
15 rows selected.
SQL>