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1555. 银行账户概要 🔒

题目描述

用户表: Users

+--------------+---------+
| Column Name  | Type    |
+--------------+---------+
| user_id      | int     |
| user_name    | varchar |
| credit       | int     |
+--------------+---------+
user_id 是这个表的主键(具有唯一值的列)。
表中的每一列包含每一个用户当前的额度信息。

 

交易表:Transactions

+---------------+---------+
| Column Name   | Type    |
+---------------+---------+
| trans_id      | int     |
| paid_by       | int     |
| paid_to       | int     |
| amount        | int     |
| transacted_on | date    |
+---------------+---------+
trans_id 是这个表的主键(具有唯一值的列)。
表中的每一列包含银行的交易信息。
ID 为 paid_by 的用户给 ID 为 paid_to 的用户转账。

 

力扣银行 (LCB) 帮助程序员们完成虚拟支付。我们的银行在表 Transaction 中记录每条交易信息,我们要查询每个用户的当前余额,并检查他们是否已透支(当前额度小于 0)。

编写解决方案报告:

  • user_id 用户 ID
  • user_name 用户名
  • credit 完成交易后的余额
  • credit_limit_breached 检查是否透支 ("Yes" 或 "No")

任意顺序返回结果表。

结果格式见如下所示。

 

示例 1:

输入:
Users 表:
+------------+--------------+-------------+
| user_id    | user_name    | credit      |
+------------+--------------+-------------+
| 1          | Moustafa     | 100         |
| 2          | Jonathan     | 200         |
| 3          | Winston      | 10000       |
| 4          | Luis         | 800         | 
+------------+--------------+-------------+

Transactions 表:
+------------+------------+------------+----------+---------------+
| trans_id   | paid_by    | paid_to    | amount   | transacted_on |
+------------+------------+------------+----------+---------------+
| 1          | 1          | 3          | 400      | 2020-08-01    |
| 2          | 3          | 2          | 500      | 2020-08-02    |
| 3          | 2          | 1          | 200      | 2020-08-03    |
+------------+------------+------------+----------+---------------+

输出:
+------------+------------+------------+-----------------------+
| user_id    | user_name  | credit     | credit_limit_breached |
+------------+------------+------------+-----------------------+
| 1          | Moustafa   | -100       | Yes                   | 
| 2          | Jonathan   | 500        | No                    |
| 3          | Winston    | 9900       | No                    |
| 4          | Luis       | 800        | No                    |
+------------+------------+------------+-----------------------+
Moustafa 在 "2020-08-01" 支付了 $400 并在 "2020-08-03" 收到了 $200 ,当前额度 (100 -400 +200) = -$100
Jonathan 在 "2020-08-02" 收到了 $500 并在 "2020-08-08" 支付了 $200 ,当前额度 (200 +500 -200) = $500
Winston 在 "2020-08-01" 收到了 $400 并在 "2020-08-03" 支付了 $500 ,当前额度 (10000 +400 -500) = $9900
Luis 未收到任何转账信息,额度 = $800

解法

方法一

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# Write your MySQL query statement below
SELECT
    t.user_id,
    user_name,
    SUM(t.credit) AS credit,
    IF(SUM(t.credit) < 0, 'Yes', 'No') AS credit_limit_breached
FROM
    (
        SELECT paid_by AS user_id, -amount AS credit FROM Transactions
        UNION ALL
        SELECT paid_to AS user_id, amount AS credit FROM Transactions
        UNION ALL
        SELECT user_id, credit FROM Users
    ) AS t
    JOIN Users AS u ON t.user_id = u.user_id
GROUP BY t.user_id;

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