C#. How to properly group from List to Dictionary?

Question

C++ / C#

There is data from the database that looks something like this:
CarId = 2, UserId = 44
CarId = 2, UserId = 45
CarId = 2, UserId = 46
CarId = 1, UserId = 90
CarId = 1, UserId = 91

I want to convert to the form CarId, List
Example:
CarId = 2, UserId = <44,45,46>
CarId = 1, UserId = <90,91>

How can this be done?

Answer 1

list.ToLookup(l => l.CarId)