Torque aggregates data points according to a timestamp variable. So first, you need to collect all your date columns into one (for instance,
new_date). As I understand from your question (and correct me if I am wrong), you only have two. If you want to generate more, you can use some of the SQL queries suggested here.
But if you are just interested in showing the starting and ending point, choose the
new_date as the
Time Column within the Wizard in the CARTO Editor and voilá! One point will appear and disappear and then another point will appear and disappear (I recommend you to low the
Duration to few seconds).
Finally, in relation to setting the
marker-width according to column value, you can find here how to do it. But basically, you will need to set
sum(size) and add these lines at the end of the autogenerated CartoCSS code:
And you will end up with a map like this: