Learning Basic SQL
Advanced SQL
SQL Functions
SQL Useful Resources
Selected Reading
© 2011 TutorialsPoint.COM
|
SQL CARTESIAN or CROSS JOINS
The CARTESIAN JOIN or CROSS JOIN returns the cartesian product of the sets of records from the two or more joined tables. Thus, it equates to an inner join where the join-condition always evaluates to True or where the join-condition is absent from the statement.
Syntax:
The basic syntax of INNER JOIN is as follows:
SELECT table1.column1, table2.column2...
FROM table1, table2 [, table3 ]
|
Example:
Consider following two tables, (a) CUSTOMERS table is as follows:
+----+----------+-----+-----------+----------+
| ID | NAME | AGE | ADDRESS | SALARY |
+----+----------+-----+-----------+----------+
| 1 | Ramesh | 32 | Ahmedabad | 2000.00 |
| 2 | Khilan | 25 | Delhi | 1500.00 |
| 3 | kaushik | 23 | Kota | 2000.00 |
| 4 | Chaitali | 25 | Mumbai | 6500.00 |
| 5 | Hardik | 27 | Bhopal | 8500.00 |
| 6 | Komal | 22 | MP | 4500.00 |
| 7 | Muffy | 24 | Indore | 10000.00 |
+----+----------+-----+-----------+----------+
|
(b) Another table is ORDERS as follows:
+-----+---------------------+-------------+--------+
| OID | DATE | ID | AMOUNT |
+-----+---------------------+-------------+--------+
| 102 | 2009-10-08 00:00:00 | 3 | 3000 |
| 100 | 2009-10-08 00:00:00 | 3 | 1500 |
| 101 | 2009-11-20 00:00:00 | 2 | 1560 |
| 103 | 2008-05-20 00:00:00 | 4 | 2060 |
+-----+---------------------+-------------+--------+
|
Now let us join these two tables using INNER JOIN as follows:
SQL> SELECT ID, NAME, AMOUNT, DATE
FROM CUSTOMERS, ORDERS;
|
This would produce following result:
+----+---------+--------+---------------------+
| ID | NAME | AMOUNT | DATE |
+----+---------+--------+---------------------+
| 1 | Ramesh | 3000 | 2009-10-08 00:00:00 |
| 1 | Ramesh | 1500 | 2009-10-08 00:00:00 |
| 1 | Ramesh | 1560 | 2009-11-20 00:00:00 |
| 1 | Ramesh | 2060 | 2008-05-20 00:00:00 |
| 2 | Ramesh | 3000 | 2009-10-08 00:00:00 |
| 2 | Ramesh | 1500 | 2009-10-08 00:00:00 |
| 2 | Ramesh | 1560 | 2009-11-20 00:00:00 |
| 2 | Ramesh | 2060 | 2008-05-20 00:00:00 |
| 3 | kaushik | 3000 | 2009-10-08 00:00:00 |
| 3 | kaushik | 1500 | 2009-10-08 00:00:00 |
| 3 | kaushik | 1560 | 2009-11-20 00:00:00 |
| 3 | kaushik | 2060 | 2008-05-20 00:00:00 |
| 4 | kaushik | 3000 | 2009-10-08 00:00:00 |
| 4 | kaushik | 1500 | 2009-10-08 00:00:00 |
| 4 | kaushik | 1560 | 2009-11-20 00:00:00 |
| 4 | kaushik | 2060 | 2008-05-20 00:00:00 |
| 5 | Hardik | 3000 | 2009-10-08 00:00:00 |
| 5 | Hardik | 1500 | 2009-10-08 00:00:00 |
| 5 | Hardik | 1560 | 2009-11-20 00:00:00 |
| 5 | Hardik | 2060 | 2008-05-20 00:00:00 |
| 6 | Komal | 3000 | 2009-10-08 00:00:00 |
| 6 | Komal | 1500 | 2009-10-08 00:00:00 |
| 6 | Komal | 1560 | 2009-11-20 00:00:00 |
| 6 | Komal | 2060 | 2008-05-20 00:00:00 |
| 7 | Muffy | 3000 | 2009-10-08 00:00:00 |
| 7 | Muffy | 1500 | 2009-10-08 00:00:00 |
| 7 | Muffy | 1560 | 2009-11-20 00:00:00 |
| 7 | Muffy | 2060 | 2008-05-20 00:00:00 |
+----+---------+--------+---------------------+
|
|
|
|