CROSS JOIN vs INNER JOIN in SQL

Question

What is the difference between CROSS JOIN and INNER JOIN?

CROSS JOIN:

SELECT 
    Movies.CustomerID, Movies.Movie, Customers.Age, 
    Customers.Gender, Customers.[Education Level], 
    Customers.[Internet Connection], Customers.[Marital Status], 
FROM   
    Customers 
CROSS JOIN 
    Movies

INNER JOIN:

SELECT 
    Movies.CustomerID, Movies.Movie, Customers.Age, 
    Customers.Gender, Customers.[Education Level], 
    Customers.[Internet Connection], Customers.[Marital Status]
FROM   
    Customers 
INNER JOIN 
    Movies ON Customers.CustomerID = Movies.CustomerID

Which one is better?

Answer 1

In contrast to inner join, which will only return 100 rows in the same scenario if there are 100 rows in each table with a 1:1 match, cross join does not combine the rows.

The outcomes of these two scenarios will be identical:

Cross join

select * from table1 cross join table2 where table1.id = table2.fk_id

Inner join

select * from table1 join table2 on table1.id = table2.fk_id

Use the last method.