A CROSS JOIN clause allows you to produce a Cartesian Product of rows in two or more tables.
Different from other join clauses such as LEFT JOIN or INNER JOIN, the CROSS JOIN clause does not have a join predicate.
Suppose you have to perform a CROSS JOIN of two tables T1 and T2.
If T1 has n rows and T2 has m rows, the result set will have nxm rows. For example, the T1 has 1,000 rows and T2 has 1,000 rows, the result set will have 1,000 x 1,000 = 1,000,000 rows.
The following illustrates the syntax of the CROSS JOIN syntax:
```
SELECT select_list
FROM T1
CROSS JOIN T2;
```
The following statement is equivalent to the above statement:
```
SELECT select_list
FROM T1, T2;
```
Also, you can use an INNER JOIN clause with a condition that always evaluates to true to simulate the cross join:
```
SELECT *
FROM T1
INNER JOIN T2 ON true;
```