计算最大价格。。。

准备的表与数据：
mysql> desc shop ;
+---------+-------------+------+-----+---------+-------+
| Field   | Type        | Null | Key | Default | Extra |
+---------+-------------+------+-----+---------+-------+
| article | varchar(20) | YES  |     | NULL    |       |
| dealer  | char(1)     | YES  |     | NULL    |       |
| price   | double      | YES  |     | NULL    |       |
+---------+-------------+------+-----+---------+-------+

mysql> select * from shop;
+---------+--------+-------+
| article | dealer | price |
+---------+--------+-------+
| 0001    | D      |  20.5 |
| 0002    | C      |  11.5 |
| 0003    | F      |  81.5 |
+---------+--------+-------+

方式1：
mysql> select s1.* from shop s1 left join shop s2 on s1.price <s2.price where s2.article is null;
+---------+--------+-------+
| article | dealer | price |
+---------+--------+-------+
| 0003    | F      |  81.5 |
+---------+--------+-------+

方式2：
mysql> select * from shop s1 where price = (select max(price) from shop s2);
+---------+--------+-------+
| article | dealer | price |
+---------+--------+-------+
| 0003    | F      |  81.5 |
+---------+--------+-------+

方式3：
mysql> select * from shop order by price desc limit 1;
+---------+--------+-------+
| article | dealer | price |
+---------+--------+-------+
| 0003    | F      |  81.5 |
+---------+--------+-------+