Hi, I have a demo data where there is start and complete time of operation with date. I want to know the time between the start and complete time, sum of the time taken, operation wise and overall total of the time. I have attached the excel for reference

You'll need to aggregate the duration of time first:

Seconds

SUM(DATEDIFF('second',[Start time],[Complete Time]))

Then we use Jonathan Drummey's calculation for the final result, with the aforementioned calc:

dd:hh:mm:ss

//replace [Seconds] with whatever field has the number of seconds in it
//and use a custom number format of 00:00:00:00 (drop the first 0 to get rid of leading 0's for days)
IIF([Seconds] % 60 == 60,0,[Seconds] % 60)// seconds
+ IIF(INT([Seconds]/60) %60 == 60, 0, INT([Seconds]/60) %60) * 100 //minutes
+ IIF(INT([Seconds]/3600) % 24 == 0, 0, INT([Seconds]/3600) % 24) * 10000 //hours
+ INT([Seconds]/86400) * 1000000 // days

Which returns the following: