Answer
IN tests whether a value equals any value in a list or subquery result. • A constant list is convenient for a small known set. • A subquery can supply the comparison values. • NULL values can make NOT IN produce an unknown result, so use it carefully.
💡 SQL Example
SELECT name FROM employees WHERE department_id IN (10, 20);
Result
Asha
Maya
⚡ Quick Revision
IN checks membership in a value set.