[LeetCode] 1581. Customer Who Visited but Did Not Make Any Transactions (JOIN)

< 문제 >

[SQL50] 1581. Customer Who Visited but Did Not Make Any Transactions (JOIN)

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< 풀이 >

SELECT A.customer_id, SUM(1) AS count_no_trans
FROM Visits A LEFT JOIN Transactions B ON A.visit_id = B.visit_id
WHERE transaction_id IS NULL
GROUP BY customer_id;