Entities
------------
Entity  | Id | Type
-------------------
Event   | 1  | Request
Stroll  | 2  | Activity
Dinner  | 3  | Activity
Angela  | 4  | Person
Anders  | 5  | Person
Michael | 6  | Person

Junctions
----------------
Left    | Right
----------------
1       | 2    // Connect Request -> Stroll
2       | 4    // Connect Stroll -> Angela
1       | 3    // Connect Request -> Dinner
3       | 5    // Connect Dinner -> Anders
3       | 6    // Connect Dinner -> Michael

Request  | Activity | Person
-----------------------------
Event    | Stroll   | Angela
         | Dinner   | Anders
                    | Michael

Person  | Request
-----------------
Angela  | Event
Anders  | Event
Michael | Event

SELECT e1.Entity Request,
       e2.Entity Activity,
       e3.Entity Person
  FROM Junctions j1
       JOIN Junctions j2
            ON j1.`Right` = j2.`Left`
       JOIN Entities e1
            ON j1.`Left` = e1.Id
       JOIN Entities e2
            ON j1.`Right` = e2.Id
       JOIN Entities e3
            ON j2.`Right` = e3.Id;

SELECT j1.`Left` Request,
       j1.`Right` Activity,
       j2.`Right` Person
  FROM Junctions j1
       JOIN Junctions j2
            ON j1.`Right` = j2.`Left`;