文章目錄
-
- 1. 題目
- 2. 解題
1. 題目
Transactions 記錄表
+----------------+---------+
| Column Name | Type |
+----------------+---------+
| id | int |
| country | varchar |
| state | enum |
| amount | int |
| trans_date | date |
+----------------+---------+
id 是這個表的主鍵。
該表包含有關傳入事務的資訊。
狀态列是類型為 [approved（已準許）、declined（已拒絕）] 的枚舉。 複制
Chargebacks 表
+----------------+---------+
| Column Name | Type |
+----------------+---------+
| trans_id | int |
| charge_date | date |
+----------------+---------+
退單包含有關放置在事務表中的某些事務的傳入退單的基本資訊。
trans_id 是 transactions 表的 id 列的外鍵。
每項退單都對應于之前進行的交易，即使未經準許。 複制
編寫一個 SQL 查詢，以查找每個月和每個國家/地區的已準許交易的數量及其總金額、退單的數量及其總金額。
注意：在您的查詢中，給定月份和國家，忽略所有為零的行。
查詢結果格式如下所示：
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 |
+------------+------------+
Result 表：
+----------+---------+----------------+-----------------+-------------------+--------------------+
| 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 |
+----------+---------+----------------+-----------------+-------------------+--------------------+ 複制
來源：力扣（LeetCode）
連結：https://leetcode-cn.com/problems/monthly-transactions-ii
著作權歸領扣網絡所有。商業轉載請聯系官方授權，非商業轉載請注明出處。
2. 解題
# Write your MySQL query statement below
select *
from
(
select t.month, t.country,
ifnull(sum(t1.approved_count),0) approved_count,
ifnull(sum(t1.approved_amount),0) approved_amount,
ifnull(sum(t2.chargeback_count),0) chargeback_count,
ifnull(sum(t2.chargeback_amount),0) chargeback_amount
from
(
select distinct country, date_format(trans_date, '%Y-%m') month
from Transactions
union
select distinct country, date_format(ch.trans_date, '%Y-%m') month
from Chargebacks ch left join Transactions tr
on ch.trans_id = tr.id
) t
left join
(
select date_format(trans_date, '%Y-%m') month,
country,
count(*) approved_count,
ifnull(sum(amount),0) approved_amount
from Transactions
where state='approved'
group by month, country
) t1
on t.month = t1.month and t.country = t1.country
left join
(
select date_format(ch.trans_date, '%Y-%m') month,
country,
count(*) chargeback_count,
ifnull(sum(amount),0) chargeback_amount
from Chargebacks ch left join Transactions tr
on ch.trans_id = tr.id
group by month, country
) t2
on t.month = t2.month and t.country = t2.country
group by month, country
) tmp
where tmp.approved_count != 0 or tmp.chargeback_count != 0 複制
or 簡單寫法，建立一個
chargeback
state
select date_format(a.trans_date,'%Y-%m') month,country,
sum(state = 'approved') approved_count,
sum(if(state = 'approved',amount,0)) approved_amount,
sum(state = 'chargeback') chargeback_count,
sum(if(state = 'chargeback',amount,0)) chargeback_amount
from
(
select *
from transactions
where state = 'approved'
union all
select id, country, 'chargeback' state, amount, c.trans_date
from chargebacks c left join transactions t
on c.trans_id = t.id
) a
group by month,country 複制