Average Order Value — Solution & ExplanationProblems / Average Order Value / EditorialApproach

GROUP BY customer_id to bucket orders per customer.

AVG(amount) computes the arithmetic mean of order amounts in each group.

ROUND(..., 2) ensures the result has exactly 2 decimal places.

Key ConceptAVG() is equivalent to SUM() / COUNT(). Like SUM(), it ignores NULLs — both in the numerator and denominator.Hints

Use AVG() to compute the mean of a numeric column.

Wrap the result in ROUND(..., 2) to get exactly 2 decimal places.