Calculate duration between 2 date columns and show output in a new column in email

[PowerUserVir]

Hi, 

Below is the MS flow that I have been working on which spits out the all tasks with Start Date and Completion Date.

The flow is working as per my expectation

I am trying to add a new column to the email output which should calculate the duration between the Outage Start Date and Outage Completion Date columns. 

I am stuck as I couldn't find any formula/expression that can calculate the new column for me?

Can someone please guide me and tell how should I calculate the duration between two date columns and if there is anything that I need to modify in the current flow to make it work as I am totally new the MS Flow?

[edgonzales]

@PowerUserVir 

Hi there.  Check out this article on Date Math in Power Automate, Moving Targets.  It might be enough to get you started in the right direction.

Good luck!

-Ed

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[PowerUserVir]

Thanks, @edgonzales  for your direction.

I tried my workflow using your direction. Below is the new changed flow.

1. I have initialized the 'Date Created' and 'Date Completed' variables

2. Then based on the value received from the list tasks, I am trying to set the value of variables (Date Created and Date Completion) and calculating the ticks at the same time with the below expression:

ticks(items('Apply_to_each')?['createdDateTime'],864000000000)

3.  When setting up the Task Variable as part of 'Iterate through Tasks', I am calculating the difference between Date Created and Date Completion variables with below expression:

sub(variables('Date Completion'),variables('DateCreated'))

the output of which is getting assigned to the 'Total Outage Time'. Total Outage Time variable will show up the difference between the dates.

I am getting the highlighted ( in red) error when trying to execute the flow

Would you be able to tell me the issue with my flow?