Code reviewHardcr-p055

Subject CorrectnessLevel Senior~18 minCommon in Code quality & review interviewsIndustries Software development

Question

Review this query that sums order totals per customer.

What a strong answer looks like

Separate real bugs from style. Rank issues by severity, point at the root cause rather than the symptom, and suggest a concrete fix — specific and kind.

Learn the concepts

Talk through your review

Code to reviewsql

1SELECT c.id, SUM(o.total)2FROM customers c3JOIN orders o ON o.customer_id = c.id4JOIN refunds r ON r.customer_id = c.id5GROUP BY c.id;

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