Question

What type of join is it when each record in the first table is matched to each record in the second table, replicating every possible combination of records between the two tables?

1) Inner join
2) Outer join
3) Cross join
4) Self join

Answer 1

A Cross join, also known as a Cartesian join, is where each record in one table is matched to every record in another table, resulting in all possible combinations of records from the two tables.

Step-by-step explanation:

The type of join where each record in the first table is matched to each record in the second table, replicating every possible combination of records between the two tables, is known as a Cross join. A Cross join can also be referred to as a Cartesian join, as it produces a Cartesian product of the two tables, meaning that if the first table has 'x' rows and the second table has 'y' rows, the result set will have 'x*y' rows. Unlike an Inner join, Outer join, or Self join, a Cross join does not require any condition to join the tables and combines all rows from the tables indiscriminately to form all possible combinations.

When each record in the first table is matched to each record in the second table, replicating every possible combination of records between the two tables, this is called a cross join.

For example, let's say we have two tables:

Table A with three records

Table B with two records

A cross join between these tables would result in six records, as it combines each record from Table A with each record from Table B, resulting in all possible combinations.