Multiple choice technology databases

We can use Group functions in the WHERE clause

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Aggregate (group) functions like COUNT, SUM, AVG, MAX, MIN cannot be used in the WHERE clause. WHERE clause filters individual rows BEFORE grouping. Aggregate functions operate on groups of rows, so they must be used in HAVING clause (which filters after grouping) or in the column list with GROUP BY. This is a fundamental SQL execution order rule.

AI explanation

Group (aggregate) functions like SUM, COUNT, AVG, MAX, and MIN operate on sets of rows and are evaluated after the WHERE clause filters rows — logically, WHERE happens before grouping/aggregation, so a group function's result isn't yet available when WHERE is being evaluated. Attempting to use one in WHERE causes a syntax/semantic error in standard SQL. Instead, filtering on an aggregate result requires the HAVING clause, which runs after grouping. So the statement is False, matching the marked answer — this is a foundational SQL ordering-of-operations rule (WHERE → GROUP BY → HAVING → SELECT → ORDER BY).

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