SQL Server - 重叠数据的累积总和 - 获取总和达到给定值的日期

In our company, our clients perform various activities that we log in different tables - Interview attendance, Course Attendance, and other general activities. I have a database view that unions data from all of these tables giving us the ActivityView that looks like this. As you can see some activities overlap - for example while attending an interview, a client may have been performing a CV update activity.In our company, our clients perform various act