SQL & PL/SQL

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!