text: #1
  CREATE TABLE shop (
  article INT(4) UNSIGNED ZEROFILL DEFAULT '0000'  NOT NULL,
  dealer VARCHAR(20) DEFAULT '' NOT NULL,  price DOUBLE(16,2) DEFAULT '0.00' NOT NULL,
  PRIMARY KEY(article, dealer));
  -- OUTPUT:
  -- Query OK, 0 rows affected, 3 warnings (0.03 sec)
  
  
  #2
  INSERT INTO shop VALUES  (1,'A',3.45),(1,'B',3.99),(2,'A',10.99),
  (3,'B',1.45),
  (3,'C',1.69),(3,'D',1.25),(4,'D',19.95);
  -- OUTPUT:
  -- Query OK, 7 rows affected (0.02 sec)
  -- Records: 7  Duplicates: 0  Warnings: 0
  
  #3
  SELECT MAX(article) AS article FROM shop;
  -- OUTPUT:
  -- +---------+
  -- | article |
  -- +---------+
  -- |       4 |
  -- +---------+
  -- 1 row in set (0.00 sec)
  
  #4
  SELECT article, dealer, price  FROM shop
  WHERE price=(SELECT MAX(price) FROM shop);
  -- OUTPUT:
  -- +---------+--------+-------+
  -- | article | dealer | price |
  -- +---------+--------+-------+
  -- |    0004 | D      | 19.95 |
  -- +---------+--------+-------+
  -- 1 row in set (0.00 sec)
  
  #5
  SELECT article, dealer, price  FROM shop
  ORDER BY price DESC  LIMIT 1;
  -- OUTPUT:
  -- +---------+--------+-------+
  -- | article | dealer | price |
  -- +---------+--------+-------+
  -- |    0004 | D      | 19.95 |
  -- +---------+--------+-------+
  -- 1 row in set (0.01 sec)
  
  #6
  SELECT article, MAX(price) AS price  FROM shop
  GROUP BY article;
  -- OUTPUT:
  -- +---------+-------+
  -- | article | price |
  -- +---------+-------+
  -- |    0001 |  3.99 |
  -- |    0002 | 10.99 |
  -- |    0003 |  1.69 |
  -- |    0004 | 19.95 |
  -- +---------+-------+
  -- 4 rows in set (0.00 sec)
  
  #7
  SELECT article, dealer, price  FROM shop s1
  WHERE price=(SELECT MAX(s2.price)
  FROM shop s2
  WHERE s1.article = s2.article); 
  -- OUTPUT:
  -- +---------+--------+-------+
  -- | article | dealer | price |
  -- +---------+--------+-------+
  -- |    0001 | B      |  3.99 |
  -- |    0002 | A      | 10.99 |
  -- |    0003 | C      |  1.69 |
  -- |    0004 | D      | 19.95 |
  -- +---------+--------+-------+
  -- 4 rows in set (0.00 sec)
  
  