This problem was appeared in Tiger Analytics Interview
Table Name : Sales
| Column Name | Type |
|---|---|
| order_date | date |
| customer | varchar |
| quantity_purchased | int |
order_date, customer is the primary key for this table.
Write a SQL query to find the count of new customers added in each Month.
Return the result table in any order.
The query result format is in the following example:
Input
Table Name: Sales
| order_date | customer | qty |
|---|---|---|
| 2021-01-01 | C1 | 20 |
| 2021-01-01 | C2 | 30 |
| 2021-02-01 | C1 | 10 |
| 2021-02-01 | C3 | 15 |
| 2021-03-01 | C5 | 19 |
| 2021-03-01 | C4 | 10 |
| 2021-04-01 | C3 | 13 |
| 2021-04-01 | C5 | 15 |
| 2021-04-01 | C6 | 10 |
Output
| order_month | customer_acquisition_count |
|---|---|
| 2021-Apr | 1 |
| 2021-Feb | 1 |
| 2021-Jan | 2 |
| 2021-Mar | 2 |