How to get a selection from the same table for different conditions?

Question

PostgreSQL

For example, there is a table in postgres:
|user_id | message |
|---------|----------------|
|1 | Bought Lada |
|1 | Bought Volvo |
|1 | Bought Kia |
|2 | Bought Lada |
|3 | Bought Kia |
|3 | Bought Kia |
There can be only 3 car brands: Lada, Volvo, Kia. Tell me how to make a request so that the answer is:
|user_id| Lada | Volvo | Kia |
| 1 | 1 | 1 | 1 |
| 2 | 1 | 0 | 0 |
| 3 | 0 | 0 | 2 |

Answer 1

SELECT
    user_id,  
    SUM(CASE WHEN (message='Купил Lada') THEN 1 ELSE 0 END) AS Lada,
    SUM(CASE WHEN (message='Купил Volvo') THEN 1 ELSE 0 END) AS Volvo,
    SUM(CASE WHEN (message='Купил Kia') THEN 1 ELSE 0 END) AS Kia
FROM 
    your_table
GROUP BY 
    user_id