Query Select Oracle PLSQL Tutorial

SQL>  create table product(
  2          product_id          integer     primary key
  3          ,price                  number(7,2)
  4          ,description            varchar2(75)
  5          ,onhand                 number(5,0)
  6          ,reorder                number(5,0)
  7          ,supplier_no            integer
  8  );
Table created.
SQL> -- product Table Inserts:
SQL> insert into product(product_id, price, description, onhand, reorder)values (1,2.50,'Happy Birthday',100,20);
1 row created.
SQL> insert into product(product_id, price, description, onhand, reorder)values (2,23.00,'Happy Birthday',null,null);
1 row created.
SQL> insert into product(product_id, price, description, onhand, reorder)values (3,null,'Happy New Year',null,null);
1 row created.
SQL> insert into product(product_id, price, description, onhand, reorder)values (4,1.50,'Happy New Year',50,10);
1 row created.
SQL>
SQL> select description, price, price * .068 as tax,
  2         price * 1.068 as "Total"
  3    from product;
DESCRIPTION
---------------------------------------------------------------------------
     PRICE        TAX      Total
---------- ---------- ----------
Happy Birthday
       2.5        .17       2.67
Happy Birthday
        23      1.564     24.564
Happy New Year
Happy New Year
       1.5       .102      1.602
4 rows selected.
SQL>
SQL> drop table product;
Table dropped.