SQL · Joins and set operations

cross join

Every row of a paired with every row of b. Use it deliberately; it multiplies row counts.

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Syntax

from a cross join b

Example

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WITH a(n) AS (VALUES (1), (2)), b(m) AS (VALUES ('x'), ('y'))
SELECT n, m FROM a CROSS JOIN b;

Reference pages are the quick answer. The course explains the why, shows the full example and ends with a challenge.