ShopKart wants to measure how many shoppers who signed up in January came back and placed another order later. Write a SQL query to calculate the retention rate for the January signup cohort.
signup_date is in January 2024.has_returned is TRUE.| Column | Type | Description |
|---|---|---|
| shopper_idPK | INT | Unique shopper identifier |
| shopper_name | VARCHAR(100) | Shopper full name |
| signup_date | DATE | Date the shopper signed up |
| has_returned | BOOLEAN | Whether the shopper returned after signup |
| country | VARCHAR(50) | Shopper country |