MySQL find the most expensive book dealers of several SQL statements _mysql

mysql> use test;
Database changed
Mysql> CREATE TABLE Shop (
-> article INT (4) UNSIGNED zerofill DEFAULT ' 0000 ' not NULL,
-> Dealer CHAR DEFAULT ' not NULL,
-> Price DOUBLE (16,2) DEFAULT ' 0.00 ' is not NULL,
-> PRIMARY KEY (article, dealer));
Query OK, 0 rows affected (0.13 sec)

Mysql> 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);
Query OK, 7 rows affected (0.03 sec)
Records:7 duplicates:0 warnings:0

Mysql> select * from shop;
+---------+--------+-------+
| Article | dealer | Price |
+---------+--------+-------+
| 0001 | A | 3.45 |
| 0001 | B | 3.99 |
| 0002 | A | 10.99 |
| 0003 | B | 1.45 |
| 0003 | C | 1.69 |
| 0003 | D | 1.25 |
| 0004 | D | 19.95 |
+---------+--------+-------+
7 rows in Set (0.06 sec)

Mysql> Select Article,max (Price) from the shop GROUP by article
->;
+---------+------------+
| Article | Max (price) |
+---------+------------+
| 0001 | 3.99 |
| 0002 | 10.99 |
| 0003 | 1.69 |
| 0004 | 19.95 |
+---------+------------+
4 rows in Set (0.05 sec)

Mysql> Select Article,max (Price), dealer from shop Group by article;
+---------+------------+--------+
| Article | Max (price) | dealer |
+---------+------------+--------+
| 0001 | 3.99 | A |
| 0002 | 10.99 | A |
| 0003 | 1.69 | B |
| 0004 | 19.95 | D |
+---------+------------+--------+
4 rows in Set (0.00 sec)

Mysql> Select Article,dealer,price from shop s1
-> where price= (select Max (S2.price) from the shop s2
-> where s1.article=s2.article);
+---------+--------+-------+
| Article | dealer | Price |
+---------+--------+-------+
| 0001 | B | 3.99 |
| 0002 | A | 10.99 |
| 0003 | C | 1.69 |
| 0004 | D | 19.95 |
+---------+--------+-------+
4 rows in Set (0.01 sec)

Mysql> 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;
+---------+--------+-------+
| Article | dealer | Price |
+---------+--------+-------+
| 0001 | B | 3.99 |
| 0002 | A | 10.99 |
| 0003 | C | 1.69 |
| 0004 | D | 19.95 |
+---------+--------+-------+
4 rows in Set (0.05 sec)

Mysql> Select S1.article,s1.dealer,s1.price from shop s1
-> left join shop S2 on S1.article=s2.article and S1.price select s1.article,s1.dealer,s1.price,s2.* from shop S1 left Join Shop S2
On S1.article=s2.article and S1.price