What happens to a database query result when the set theory principle of 'union' combines two tables with completely disjoint sets of primary keys?

💡 Explanation

A 'union' operation, by set theory definition, creates a new set containing all distinct elements from both original sets; because the primary keys are disjoint, no overlap exists, therefore the resulting set contains all elements from both, forming a larger set, rather than filtering or reducing the set.

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