Your growth team wants to identify customers who are active on both the mobile app and the web platform. Using the mobile_users and web_users tables, return the customer_id of every customer who appears in both. Sort by customer_id.
mobile_users
| column | type |
|---|---|
| customer_id | INTEGER |
| last_active | DATE |
web_users
| column | type |
|---|---|
| customer_id | INTEGER |
| last_active | DATE |
mobile_users
| customer_id | last_active |
|---|---|
| 1 | 2024-03-01 |
| 2 | 2024-03-05 |
| 3 | 2024-03-10 |
web_users
| customer_id | last_active |
|---|---|
| 2 | 2024-03-04 |
| 3 | 2024-03-09 |
| 4 | 2024-03-11 |
| customer_id |
|---|
| 2 |
| 3 |
Customers 2 and 3 appear in both tables. Customer 1 is mobile-only, customer 4 is web-only, so neither is returned.