int id = ...;
string name;
int salary;

sql << "select name, salary from persons where id = " << id,
       into(name), into(salary);

int id = ...;
Person p;

sql << "select first_name, last_name, date_of_birth "
       "from persons where id = " << id,
       into(p);

Rowset<string> rs = (sql.prepare << "select name from persons");
copy(rs.begin(), rs.end(), ostream_iterator<string>(cout, "\n"));