creating matrix table help need with columns and relationship

Hi All,

I am trying to create a matrix table visual.

The part that I am struggling with is the columns name that should be present there and the values. 
The layout shoud be the following:

So here is what I have at the moment.

First table name 'history'. the important columns are:
request id: key mapping to the request.
event name: created, assigned,completed.
event date: dates of the above

second table:
id: request id,
project name: name of the proj that the request is associated to.


I can calculeted that datediffs . I jsut dont have any idea how to come up with the matrix. Any help will be very much appreciated.