CROSS JOIN and All Combinations

Combine Every Pair of Rows

CROSS JOIN combines each left-side row with every right-side row. N left rows and M right rows produce N × M rows. Combining two tables without a join condition produces the same set of all combinations as a CROSS JOIN.

GOAL

Calculate the result row count of a CROSS JOIN.

How many rows result from CROSS JOINing 6 customers with 7 products?

CHECK IT

customers2 rows

id	name
1	Alice
2	Bob

products3 rows

id	name
1	Pixel Phone
2	iPhone
3	ThinkPad

There are 2 customers rows on the left and 3 products rows on the right. CROSS JOIN has no row-matching condition.