MySQL Tutorial/Table Join/Natural Join

Three-Table NATURAL JOIN

mysql>
mysql>
mysql> CREATE TABLE Books(
    ->    BookID SMALLINT NOT NULL PRIMARY KEY,
    ->    BookTitle VARCHAR(60) NOT NULL,
    ->    Copyright YEAR NOT NULL
    -> )
    -> ENGINE=INNODB;
Query OK, 0 rows affected (0.05 sec)
mysql>
mysql>
mysql> INSERT INTO Books VALUES (12786, "Java",           1934),
    ->                          (13331, "MySQL",          1919),
    ->                          (14356, "PHP",            1966),
    ->                          (15729, "PERL",           1932),
    ->                          (16284, "Oracle",         1996),
    ->                          (17695, "Pl/SQL",         1980),
    ->                          (19264, "JavaScript",     1992),
    ->                          (19354, "www.sqle.ru", 1993);
Query OK, 8 rows affected (0.02 sec)
Records: 8  Duplicates: 0  Warnings: 0
mysql>
mysql>
mysql> CREATE TABLE Authors(
    ->    AuthID SMALLINT NOT NULL PRIMARY KEY,
    ->    AuthFN VARCHAR(20),
    ->    AuthMN VARCHAR(20),
    ->    AuthLN VARCHAR(20)
    -> )
    -> ENGINE=INNODB;
Query OK, 0 rows affected (0.05 sec)
mysql>
mysql>
mysql> INSERT INTO Authors VALUES (1006, "H", "S.", "T"),
    ->                            (1007, "J", "C",  "O"),
    ->                            (1008, "B", NULL, "E"),
    ->                            (1009, "R", "M",  "R"),
    ->                            (1010, "J", "K",  "T"),
    ->                            (1011, "J", "G.", "N"),
    ->                            (1012, "A", NULL, "P"),
    ->                            (1013, "A", NULL, "W"),
    ->                            (1014, "N", NULL, "A");
Query OK, 9 rows affected (0.05 sec)
Records: 9  Duplicates: 0  Warnings: 0
mysql>
mysql>
mysql> CREATE TABLE AuthorBook(
    ->    AuthID SMALLINT NOT NULL,
    ->    BookID SMALLINT NOT NULL,
    ->    PRIMARY KEY (AuthID, BookID),
    ->    FOREIGN KEY (AuthID) REFERENCES Authors (AuthID),
    ->    FOREIGN KEY (BookID) REFERENCES Books (BookID)
    -> )
    -> ENGINE=INNODB;
Query OK, 0 rows affected (0.05 sec)
mysql>
mysql>
mysql> INSERT INTO AuthorBook VALUES (1006, 14356),
    ->                               (1008, 15729),
    ->                               (1009, 12786),
    ->                               (1010, 17695),
    ->                               (1011, 15729),
    ->                               (1012, 19264),
    ->                               (1012, 19354),
    ->                               (1014, 16284);
Query OK, 8 rows affected (0.05 sec)
Records: 8  Duplicates: 0  Warnings: 0
mysql>
mysql>
mysql> select * from Authors;
+--------+--------+--------+--------+
| AuthID | AuthFN | AuthMN | AuthLN |
+--------+--------+--------+--------+
|   1006 | H      | S.     | T      |
|   1007 | J      | C      | O      |
|   1008 | B      | NULL   | E      |
|   1009 | R      | M      | R      |
|   1010 | J      | K      | T      |
|   1011 | J      | G.     | N      |
|   1012 | A      | NULL   | P      |
|   1013 | A      | NULL   | W      |
|   1014 | N      | NULL   | A      |
+--------+--------+--------+--------+
9 rows in set (0.01 sec)
mysql> select * from Books;
+--------+----------------+-----------+
| BookID | BookTitle      | Copyright |
+--------+----------------+-----------+
|  12786 | Java           |      1934 |
|  13331 | MySQL          |      1919 |
|  14356 | PHP            |      1966 |
|  15729 | PERL           |      1932 |
|  16284 | Oracle         |      1996 |
|  17695 | Pl/SQL         |      1980 |
|  19264 | JavaScript     |      1992 |
|  19354 | www.sqle.ru |      1993 |
+--------+----------------+-----------+
8 rows in set (0.00 sec)
mysql> select * from AuthorBook;
+--------+--------+
| AuthID | BookID |
+--------+--------+
|   1009 |  12786 |
|   1006 |  14356 |
|   1008 |  15729 |
|   1011 |  15729 |
|   1014 |  16284 |
|   1010 |  17695 |
|   1012 |  19264 |
|   1012 |  19354 |
+--------+--------+
8 rows in set (0.00 sec)
mysql>
mysql> SELECT BookTitle, Copyright,
    ->    CONCAT_WS(" ", AuthFN, AuthMN, AuthLN) AS Author
    -> FROM Books AS b NATURAL JOIN AuthorBook AS ab
    ->    NATURAL JOIN Authors AS a
    -> WHERE Copyright<1980
    -> ORDER BY BookTitle;
+-----------+-----------+--------+
| BookTitle | Copyright | Author |
+-----------+-----------+--------+
| Java      |      1934 | R M R  |
| PERL      |      1932 | B E    |
| PERL      |      1932 | J G. N |
| PHP       |      1966 | H S. T |
+-----------+-----------+--------+
4 rows in set (0.00 sec)
mysql>
mysql> drop table AuthorBook;
Query OK, 0 rows affected (0.03 sec)
mysql> drop table Books;
Query OK, 0 rows affected (0.05 sec)
mysql> drop table Authors;
Query OK, 0 rows affected (0.05 sec)