Code RoomNOT IN with nulls fails
MediumPrep Room Coding #2386

NOT IN with nulls fails

Code reviewCode quality & reviewMid–Senior~18 min

Review this query to find customers with no orders.

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.

0:00 of about 18 min
Mark a line and say what kind of problem it is.0 findings
1SELECT * FROM customers
2WHERE id NOT IN (SELECT customer_id FROM orders);
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.