Table: 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 “[”批准“,”拒绝“] 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。
查询结果格式如下所示:
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 |
+------+---------+----------+--------+------------+
Result table:
+----------+---------+-------------+----------------+--------------------+-----------------------+
| 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 |
+----------+---------+-------------+----------------+--------------------+-----------------------+
来源:力扣(LeetCode) 链接:https://leetcode-cn.com/problems/monthly-transactions-i 著作权归领扣网络所有。商业转载请联系官方授权,非商业转载请注明出处。
# Write your MySQL query statement below
select date_format(trans_date, '%Y-%m') month,
country,
count(*) trans_count,
sum(case state when 'approved' then 1
else 0 end) approved_count,
sum(amount) trans_total_amount,
sum(if(state='approved', amount, 0)) approved_total_amount
from Transactions
group by date_format(trans_date, '%Y-%m'), country
# %M 输出的是英文的月份,%m是两位数字
# %Y 输出4为年份, %y 输出年分的后两位