How to show multiple fields in filter selectbox

[mjhcremer]

Table Users
id
first_name
last_name

Example: 1, John, Doe

Table Declarations
id
user_id
amount

Example: 1, 1, 100

Now I want to create a power table for the model declarations.
The column user_id I want to be displayed as John Doe.
The filter for the column I want as a InputSelect with the values like John Doe.

Is there someone that knows an example or a solution the achieve this?