Seems a bit unconventional to manually specify which index you'd like to use when writing queries. This would normally be something handled by a query optimizer.
Of course, many DBMS provide some facility for specifying indices manually through query hinting, but for non-trivial queries, the optimizer often can do a better job than a programmer at picking the most efficient query plan.
Of course, many DBMS provide some facility for specifying indices manually through query hinting, but for non-trivial queries, the optimizer often can do a better job than a programmer at picking the most efficient query plan.