The number of elements in a Cartesian product is equal to the product in the number of elements of each set. The idea of a Cartesian product is that you combine each element from set A with each element from set B. If the product set (the Cartesian product) of sets A and B has a finite number of elements, this may be due to the fact that both A and B are finite. However, there is another possibility: that one of the sets, for example, set A, has zero elements, and the other is infinite. In this case, the Cartesian product would also have zero elements.

Cartesian product is the name that refers to the set of the ordered pairs. The Cartesian product of two sets A and B is AB.

A Cartesian product of two sets is a set that contains all ordered pairs, such that the first item is from the first set and the second item from the second set. (It can be the same set twice, instead of two different sets.) For example, the Cartesian product of the sets {A, B} and {1, 2, 3} is the set of pairs:

{(A, 1), (A, 2), (A, 3), (B, 1), (B, 2), (B, 3)}

In general, the Cartesian product has a number of elements that is the product of the number of elements of the two products that make it up. A Cartesian product can also be defined for more than two sets.

Cartesian products are very important as the basis of mathematics. For example, relations are subsets of Cartesian products. Note that functions are a special type of relation.

The Cartesian product of two sets, A and B, where A has m distinct elements and B has n, is the set of m*n ordered pairs. The magnitude is, therefore m*n.

Difference Between CARTESIAN PRODUCT & NATURAL JOINT

Cartesian product is like the cross product ie every element of one row of one table/entity is multiplied to every column of another table for solving linked queries of two tables ...

Where as natural Join is simply joining two or more entities eliminating the common attributes or columns..

@nayan answered it :)