1193.-monthly-transactions-i.md

1193. Monthly Transactions I

Problem

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                  |
+----------+---------+-------------+----------------+--------------------+-----------------------+

MySQL

Result

Runtime: 598 ms, Beats 80.34% of users with MySQL

SQL Schema

Create table If Not Exists Transactions
(
    id         int,
    country    varchar(4),
    state      enum ('approved', 'declined'),
    amount     int,
    trans_date date
);

Truncate table Transactions;

insert into Transactions (id, country, state, amount, trans_date)
values ('121', 'US', 'approved', '1000', '2018-12-18');

insert into Transactions (id, country, state, amount, trans_date)
values ('122', 'US', 'declined', '2000', '2018-12-19');

insert into Transactions (id, country, state, amount, trans_date)
values ('123', 'US', 'approved', '2000', '2019-01-01');

insert into Transactions (id, country, state, amount, trans_date)
values ('124', 'DE', 'approved', '2000', '2019-01-07');

Solution

select date_format(trans_date, '%Y-%m')       as month,
       country,
       count(id)                              as trans_count,
       sum(state = 'approved')                as approved_count,
       sum(if(amount, amount, 0))             as trans_total_amount,
       sum(if(state = 'approved', amount, 0)) as approved_total_amount
from Transactions
group by month, country
order by month;