Query for hours at work each day

I have an SQL table “tasks”. The table has a date_performed and a begin_time and end_time of each task.

I have been asked by a client to generate a report of the time the service guy was “at work” for each day (not a sum of the job times). This is defined as the time between the start_time of the first task each day to the end_time of the last task.
They want a table with the date and hours at work for any given date range they specify.

The number of jobs each day is variable but luckily no jobs go past midnight.

Any help appreciated…

What’s the question? Do you need help with a query to find the time difference or help with setting up a table to record the hours?