参考：

• The Rows Holding the Group-wise Maximum of a Certain Column -- MySQL 手册
• How can I SELECT rows with MAX(Column value), DISTINCT by another column in SQL? -- Stack overflow

用 Uncorrelated subquery:

SELECT s1.article, dealer, s1.price
FROM shop s1
JOIN (
  SELECT article, MAX(price) AS price
  FROM shop
  GROUP BY article) AS s2
  ON s1.article = s2.article AND s1.price = s2.price;

解释：分两步

• 第一步：取 MAX 和 GROUP BY 的字段的记录
• 第二步：取上述记录所在的行

用 LEFT JOIN:

SELECT s1.article, s1.dealer, s1.price
FROM shop s1
LEFT JOIN shop s2 ON s1.article = s2.article AND s1.price < s2.price
WHERE s2.article IS NULL;

解释：s1.price 为最大值时，s2.article 就已经是 NULL 了。