#1581 Customer Who Visited but Did Not Make Any Transactions

https://leetcode.com/problems/customer-who-visited-but-did-not-make-any-transactions/

MS SQL Server

SELECT customer_id, COUNT(*) 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