Page 54 - Modular_V2.0_SQL_Flipbook

Output:
+----------+-------+-------+-----------+
| Stu_name | Age | Fees | Transport |
+----------+-------+-------+-----------+
| Rahim | 18 | 12000 | 2000 |
+----------+-------+-------+-----------+
| Raja | 19 | 13000 | 3000 |
+----------+-------+-------+-----------+
| Riya | 18 | 12000 | 5000 |
+----------+-------+-------+-----------+
Before diving into the specifics, let’s visualise how each type of join operates in combining data from
two tables:

Cartesian Product

The Cartesian product is also known as cross product. It is denoted by X. The degree of the new
relation will be the sum of the degrees of two relations in which cross product is executed.
Syntax:

SELECT * FROM table1, table2;

or
SELECT table1.col1, table2.col2 FROM table1, table2;

Let us consider the following tables:

Table-STUDENTS Table-SUBJECTS

Roll_no Name Subject Teacher
1 Rohit Maths Mr. Rakesh
2 Amisha English Ms. Pooja

Select * from STUDENTS, SUBJECTS;

or
SELECT STUDENTS.Roll_no, STUDENTS.Name, SUBJECTS.Subject, SUBJECTS.Teacher
FROM STUDENTS, SUBJECTS;
STUDENTS X SUBJECTS will be:
+---------+--------+---------+------------+
| Roll_no | Name | Subject | Teacher |
+---------+--------+---------+------------+
| 2 | Amisha | Maths | Mr. Rakesh |
+---------+--------+---------+------------+
| 1 | Rohit | Maths | Mr. Rakesh |
+---------+--------+---------+------------+
| 2 | Amisha | English | Ms. Pooja |
+---------+--------+---------+------------+
| 1 | Rohit | English | Ms. Pooja |
+---------+--------+---------+------------+

Columns after Cartesian Product: C1 + C2 = 2 + 2 = 4 columns ( Roll_No, Name, Subject, Teacher)

Rows after Cartesian Product: R1 × R2 = 2 × 2 = 4 rows (Every student is paired with every subject)

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