(SQL) - LeetCode (easy) 1581. Customer Who Visited but Did Not Make Any Transactions

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

join을 사용해본 문제였습니다.

📕 풀이방법

📔 풀이과정

visit_id로 visits와 transactions table을 join한 후 customer_id로 goup by햐 transaction_id가 null인 column의 visit_id를 count해 준 후 customer_id와 함께 select합니다.

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📕 Code

📔 ANSI SQL

select v.customer_id, count(v.visit_id) as count_no_trans
from visits v
left join transactions t on v.visit_id = t.visit_id
where t.transaction_id is null
group by v.customer_id

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*더 나은 내용을 위한 지적, 조언은 언제나 환영합니다.