Leetcode Note: MySQL - Customer Who Visted but Did Not Make Any Transactions
Customer Who Visited but Did Not Make Any Transactions - LeetCode
https://leetcode.com/problems/customer-who-visited-but-did-not-make-any-transactions/
- Go 言語で取り組んだメモ
回答
Simplest - Just a LEFT JOIN - No SUB-Query. - Customer Who Visited but Did Not Make Any Transactions - LeetCode
https://leetcode.com/problems/customer-who-visited-but-did-not-make-any-transactions/solutions/865760/simplest-just-a-left-join-no-sub-query/
SELECT
customer_id,
COUNT(Visits.visit_id) AS count_no_trans
FROM
visits
LEFT JOIN Transactions
ON Visits.visit_id = Transactions.visit_id
WHERE
Transactions.visit_id IS NULL
GROUP BY customer_id