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1193. Monthly Transactions I
Description
Table: Transactions
+---------------+---------+ | Column Name | Type | +---------------+---------+ | id | int | | country | varchar | | state | enum | | amount | int | | trans_date | date | +---------------+---------+ id is the primary key of this table. The table has information about incoming transactions. The state column is an enum of type ["approved", "declined"].
Write an SQL query to find for each month and country, the number of transactions and their total amount, the number of approved transactions and their total amount.
Return the result table in any order.
The query result format is in the following example.
Example 1:
Input: 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 | +------+---------+----------+--------+------------+ Output: +----------+---------+-------------+----------------+--------------------+-----------------------+ | 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 | +----------+---------+-------------+----------------+--------------------+-----------------------+
Solutions
Solution 1: Grouping and Aggregation
We can first group by month and country, and then use the COUNT and SUM functions to respectively calculate the number of transactions, the number of approved transactions, the total amount, and the total amount of approved transactions for each group.
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# Write your MySQL query statement below SELECT DATE_FORMAT(trans_date, '%Y-%m') AS month, country, COUNT(1) AS trans_count, SUM(state = 'approved') AS approved_count, SUM(amount) AS trans_total_amount, SUM(IF(state = 'approved', amount, 0)) AS approved_total_amount FROM Transactions GROUP BY 1, 2;