表：Transactions
+---------------+---------+
| 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。
state 列类型为 ["approved", "declined"] 之一编写一个 sql 查询来查找每个月和每个国家/地区的事务数及其总金额、已批准的事务数及其总金额。
以 任意顺序 返回结果表。
查询结果格式如下所示。
输入：
Transactions table:
+------+---------+----------+--------+------------+
| id | country | state | amount | trans_date |
+------+---------+----------+--------+------------+
| 121 | US | approved | 1000 | 2018-12-18 |
| 122 | US | declined | 2000 | 2018-12-19 |
| 123 | US | approved | 2000 | 2019-01-01 |
| 124 | DE | approved | 2000 | 2019-01-07 |
+------+---------+----------+--------+------------+
输出：
+----------+---------+-------------+----------------+--------------------+-----------------------+
| month | country | trans_count | approved_count | trans_total_amount | approved_total_amount |
+----------+---------+-------------+----------------+--------------------+-----------------------+
| 2018-12 | US | 2 | 1 | 3000 | 1000 |
| 2019-01 | US | 1 | 1 | 2000 | 2000 |
| 2019-01 | DE | 1 | 1 | 2000 | 2000 |
+----------+---------+-------------+----------------+--------------------+-----------------------+
sql
with cte1 as(
select
Transactions.*,
DATE_FORMAT(trans_date,'%Y-%m') as 'month'
from
Transactions
),
cte2 as(
select cte1.month,country,
ifnull(count(1),0) as trans_count,
ifnull(sum(amount),0) as trans_total_amount
from cte1
group by cte1.month,country
),
cte3 as(
select cte1.month,country,
ifnull(count(1),0) as approved_count,
ifnull(sum(amount),0) as approved_total_amount
from cte1
where state='approved'
group by cte1.month,country
)
select cte2.month,cte2.country,
trans_count,
ifnull(approved_count,0) as approved_count,
trans_total_amount,
ifnull(approved_total_amount,0) as approved_total_amount
from cte2 left join cte3
on cte2.month=cte3.month and cte2.country=cte3.country