LeetCode（数据库）- 银行账户概要

题目链接：​​点击打开链接​​

题目大意：略。

解题思路：略。

AC 代码

WITH t1 AS(SELECT user_id, credit FROM Users
UNION ALL 
SELECT paid_by, -amount FROM Transactions
UNION ALL 
SELECT paid_to, amount FROM Transactions)

SELECT user_id, user_name, SUM(t1.credit) credit, IF(SUM(t1.credit) > 0, 'No', 'Yes') credit_limit_breached
FROM t1 JOIN Users USING(user_id)
GROUP BY user_id