Mega Code Archive
Using EXISTS with subquery
<![CDATA[
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 (0.06 sec)
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.rntsoft.com', 1993);
Query OK, 8 rows affected (0.05 sec)
Records: 8 Duplicates: 0 Warnings: 0
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 (0.06 sec)
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> 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 (0.06 sec)
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> 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 (0.00 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.rntsoft.com | 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 BookID, BookTitle
-> FROM Books AS b
-> WHERE EXISTS
-> (
-> SELECT BookID
-> FROM AuthorBook AS ab
-> WHERE b.BookID=ab.BookID
-> )
-> ORDER BY BookTitle;
+--------+----------------+
| BookID | BookTitle |
+--------+----------------+
| 12786 | Java |
| 19264 | JavaScript |
| 16284 | Oracle |
| 15729 | PERL |
| 14356 | PHP |
| 17695 | Pl/SQL |
| 19354 | www.rntsoft.com |
+--------+----------------+
7 rows in set (0.00 sec)
mysql>
mysql> drop table AuthorBook;
Query OK, 0 rows affected (0.02 sec)
mysql> drop table Books;
Query OK, 0 rows affected (0.06 sec)
mysql> drop table Authors;
Query OK, 0 rows affected (0.06 sec)
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