A CROSS JOIN query will return all records where each row from the first table is combined with each row from the second table. This
means that such a query returns the Cartesian product of the sets of rows from the joined tables, which is why it is also know as "Cartesian product
query".
Such a query can return a huge amount of data, and therefore should be used only with great caution and only when really needed.
Noncompliant code example
BEGIN
-- Standard ANSI syntax
SELECT *
INTO employeeArray
FROM employee CROSS JOIN department; -- Noncompliant; explicit cross join
END;
/
BEGIN
-- Old syntax
SELECT *
INTO employeeArray
FROM employee, department; -- Noncompliant; also a cross join
END;
/
