thinQmaster Virtual testing partner Adaptive practice exams that find your weak spots and drill them. Every answer explained. From $69
Enroll

thinQmaster

Find your exam

Five questions free, before you decide.

Step 1 · choose a vendor

In one of our camps? Your practice exams come with the tuition — they are on your study page already.

Data & Analytics · Intermediate

Cartesian Product

The set of all possible row pairings between two tables, produced by a cross join or a missing join condition.

Definition

Cartesian products grow multiplicatively and are a common cause of runaway queries and inflated totals. Old-style comma joins without a WHERE predicate create them by accident.

Example

SELECT * FROM A, B; -- no WHERE produces a Cartesian product

Exam tip

Row counts equal to rows(A) × rows(B) signal a Cartesian product.

Related terms