There are two error in the first query (Cashiers + shifts worked). First of all, you should use the WorkingShifts document, not the ShiftSchedule register. It wasn't clearly said in the task description, so I fixed this.
Secondly, you needed to exclude cashiers without any shifts worked from the output using the JOIN clause. I added a new Cashier that has no WorkingShifts and now your output and the control output are different. If you're not sure how to filter the query output with JOIN, please, watch this episode.
Joined: Dec 2, 2018
Company: 1C Innovation VietNam
In your first query, you should use the Cashiers catalog to join with the WorkingShifts document (not the ShiftSchedule register) and get Cashier from the catalog. Moreover, you need to exclude cashiers without any shifts worked, so it should be document.WorkingShifts Left join catalog.Cashiers. The same for the second query (catalog.Cashiers and catalog.Agreements).