Question

1205. 每月交易 II

English Version

题目描述

Transactions 记录表

+----------------+---------+
| Column Name  | Type  |
+----------------+---------+
| id       | int   |
| country    | varchar |
| state      | enum  |
| amount     | int   |
| trans_date   | date  |
+----------------+---------+
id 是这个表的主键。
该表包含有关传入事务的信息。
状态列是枚举类型，值为 [approved、declined] 其中之一的列。

Chargebacks 表

+----------------+---------+
| Column Name  | Type  |
+----------------+---------+
| trans_id     | int   |
| trans_date   | date  |
+----------------+---------+
退单包含有关放置在事务表中的某些事务的传入退单的基本信息。
trans_id 是 transactions 表的 id 列的外键（reference 列）。
每项退单都对应于之前进行的交易，即使未经批准。

 

编写一个解决方案，找出每个国家/地区的每月交易信息：已批准交易的数量及其总金额、退单的数量及其总金额。

注意：在你的解决方案中，只需显示给定月份和国家，忽略所有为零的行。

以 任意顺序 返回结果表。

结果格式如下所示。

 

示例 1:

输入：
Transactions 表：
+-----+---------+----------+--------+------------+
| id  | country | state  | amount | trans_date |
+-----+---------+----------+--------+------------+
| 101 | US    | approved | 1000   | 2019-05-18 |
| 102 | US    | declined | 2000   | 2019-05-19 |
| 103 | US    | approved | 3000   | 2019-06-10 |
| 104 | US    | declined | 4000   | 2019-06-13 |
| 105 | US    | approved | 5000   | 2019-06-15 |
+-----+---------+----------+--------+------------+
Chargebacks 表：
+----------+------------+
| trans_id | trans_date |
+----------+------------+
| 102    | 2019-05-29 |
| 101    | 2019-06-30 |
| 105    | 2019-09-18 |
+----------+------------+
输出：
+---------+---------+----------------+-----------------+------------------+-------------------+
| month   | country | approved_count | approved_amount | chargeback_count | chargeback_amount |
+---------+---------+----------------+-----------------+------------------+-------------------+
| 2019-05 | US    | 1        | 1000      | 1        | 2000        |
| 2019-06 | US    | 2        | 8000      | 1        | 1000        |
| 2019-09 | US    | 0        | 0         | 1        | 5000        |
+---------+---------+----------------+-----------------+------------------+-------------------+

解法

方法一

# Write your MySQL query statement below
WITH
  T AS (
    SELECT * FROM Transactions
    UNION
    SELECT id, country, 'chargeback', amount, c.trans_date
    FROM
      Transactions AS t
      JOIN Chargebacks AS c ON t.id = c.trans_id
  )
SELECT
  DATE_FORMAT(trans_date, '%Y-%m') AS month,
  country,
  SUM(state = 'approved') AS approved_count,
  SUM(IF(state = 'approved', amount, 0)) AS approved_amount,
  SUM(state = 'chargeback') AS chargeback_count,
  SUM(IF(state = 'chargeback', amount, 0)) AS chargeback_amount
FROM T
GROUP BY 1, 2
HAVING approved_amount OR chargeback_amount;