Valid fix for non-grouped column

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Accepted Answer

The problem is name - it is not in GROUP BY and not wrapped in an aggregate. The cleanest fix is to remove name from the SELECT list so every remaining column is either in GROUP BY or aggregated. Dropping GROUP BY entirely (option B) still fails because MAX(salary) is an aggregate while name is not, so the same error remains. Adding HAVING name IS NOT NULL (option C) fails because name is still not grouped or aggregated - HAVING cannot reference it either. GROUP BY dept, MAX(salary) (option D) is a syntax error - you cannot GROUP BY an aggregate expression.