HANA SQL Logic or Calculation view Model level Approach for time dependent role mapping

I have a Time dependent Master data table – DRNUMBER

Recently with new CLASS – ‘1TC’, ECC folks introduced Role information. Earlier with CLASS - ‘1JL’ role information will not be available.

CLASS - 1JL is some what detail level and CLASS - 1TC is aggregated level if same role is performed with continued dates.

Expected output should look like below. How to achieve this in HANA - SQL and if Calculation view Model level is possible how it is…..