How to sum the results of a duration calculation

[Jacob_Steagald]

I am using Power BI to try and calculate Units Picked Per Hour and in order to do that I need to calculate Hours Worked

Each employee has multiple work orders and each work order has a first and a last item scanned. I am using a basic DATEDIFF function (MAX pick time minus MIN pick time) to calculate the time between the first scan and the last scan of each work order to calculate the time the employee was picking.

However, when I try to look at the TOTAL of those durations for each worker it gives me the difference between the employees first and last pick and the duration is incorrect. 

Name	Work ID	Pick Time	Units Picked
John Smith	123	8:15 am	2
John Smith	123	8:16 am	2
John Smith	123	8:19 am	2
John Smith	123	8:22 am	2
John Smith	456	8:45 am	5
John Smith	456	8:50 am	5
John Smith	456	8:55 am	5

So, I used a DATEDIFF to calculate the duration of work ID 123 and 456 and it returns 7 minutes and 10 minutes respectively. That's great. However, if I calculate the duration for John Smith it gives me the INCORRECT 40 minutes because its taking the MAX time minus the MIN time. 

How can I create a function that finds the DATEDIFF for each work assignment and then SUMS them for each individual working?

[parry2k · Accepted solution]

@Jacob_Steagald try this measure to calculate the time between min and max

Pick Time Duration = 
SUMX ( 
    SUMMARIZE ( 
        PickTime, 
        PickTime[Name], 
        PickTime[Work ID], 
        "@Min", MIN ( [Pick Time] ), 
        "@Max", MAX ( PickTime[Pick Time] ) 
    ), 
    DATEDIFF ( [@Min], [@Max], MINUTE ) 
)

[Jacob_Steagald]

Kudos! Thanks, my friend!