Sum total hours each of month

[anonymous]

I want to sum total hours of that month. But it shows 0 hour. How I can do it?

[Marc_Dillon]

Is that column a Duration type?

[anonymous]

I did it. I only want to sum them

[Aurelien]

What about that ?

I think you wish to use the 5th example:
TOTALHOURS(SUM(LIST("024:00:00", "000:15:00", "000:00:18")))