Calculating count of events in 15 minute datetime intervals

[RandomDenny]

I have a table of VPN session start and end times and I need to plot active sessions across time in 15 minute increments.

So for each 15 minute block (12:00, 12:15, 12:45 etc) I need the count of sessions opened that day before that block, minus the count of sessions ended that day before that block.

I started down the path of trying to create a datetime calendar with the 15 minute blocks first, but I'm a newbie to this so I thought I might post and see if there's a simpler way. 

Thanks

[amitchandak]

@RandomDenny , refer if this can fill

https://kohera.be/blog/power-bi/how-to-create-a-time-table-in-power-bi-in-a-few-simple-steps/

[RandomDenny]

That is actually the path I started down,

I created a Date Table:

Date = CALENDAR(DATE(2020,1,1),TODAY())

And I created a TimeTable

TimeTable =

VAR HourTable = SELECTCOLUMNS(GENERATESERIES((0), (23)), "Hour", [Value])

VAR MinuteTable = SELECTCOLUMNS(GENERATESERIES((0), (59), 15), "Minute", [Value])

RETURN

ADDCOLUMNS(

CROSSJOIN(HourTable, MinuteTable),

"Time", TIME([Hour], [Minute], 0)

)

The "Time" column gives me a Datetime value that is in the 15 minute blocks like I want, but it's generating dates that are in 1899. ?! I need this column to have the date values from the Date table, but with the time part of the value in the 15 minute blocks as they are now.

So instead of

I need the Time column to look like

01/01/2020 12:00:00 AM

01/01/2020 12:15:00 AM

01/01/2020 12:30:00 AM

01/01/2020 12:45:00 AM

Etc.

Then there is still the matter of the calculations, which I think might be straightforward enough if I can get this table in the format that I want. But that was where I decided to post and make sure I wasn't missing a simpler way.