select语句将一个表中的列相乘，然后从另一个表中添加列

mysql> select * from orders;
+---------+------------+------------+------------+----------+----------+
| orderid | customerid | orderdate  | shipdate   | shipping | salestax |
+---------+------------+------------+------------+----------+----------+
|       1 |          1 | 2008-03-31 | 2008-03-31 |     4.99 |     5.00 | 
|       2 |          1 | 2008-04-01 | 2008-04-02 |     5.99 |     5.00 | 
|       3 |          2 | 2008-04-01 | 2008-04-02 |     3.99 |     6.00 | 
|       4 |          3 | 2008-04-02 | 2008-04-02 |     6.99 |     7.50 | 
+---------+------------+------------+------------+----------+----------+
4 rows in set (0.02 sec)
mysql> select * from orderinfo;
+---------+------------+-----+-------+----------+
| orderid | isbn       | qty | price | detailid |
+---------+------------+-----+-------+----------+
|       1 | 0929306279 |   1 | 29.95 |        1 | 
|       1 | 0929306260 |   1 | 49.95 |        2 | 
|       2 | 0439357624 |   3 | 16.95 |        3 | 
|       3 | 0670031844 |   1 | 34.95 |        4 | 
|       4 | 0929306279 |   1 | 29.95 |        5 | 
|       4 | 0929306260 |   1 | 49.95 |        6 | 
|       4 | 0439357624 |   1 | 16.95 |        7 | 
|       4 | 0670031844 |   1 | 34.95 |        8 | 
+---------+------------+-----+-------+----------+
8 rows in set (0.00 sec)
mysql> select * from orders;
+---------+-------