Aggregate Functions Oracle PLSQL Tutorial

SQL>  CREATE TABLE sales(
  2    product_id            NUMBER(6),
  3    cid           NUMBER,
  4    time_id               DATE,
  5    channel_id            CHAR(1),
  6    promo_id              NUMBER(6),
  7    sold         NUMBER(3),
  8    amount                NUMBER(10,2),
  9    cost                  NUMBER(10,2)
 10  );
Table created.
SQL>
SQL> select sum(amount)
  2  from sales
  3  where time_id between to_date('2006-02-01', 'YYYY-MM-DD') and to_date('2006-02-28', 'YYYY-MM-DD');
SUM(AMOUNT)
-----------
1 row selected.
SQL>
SQL> drop table sales;
Table dropped.