Average of percent of column totals in DAX - powerbi

Question

I have a fact table named meetings containing the following:
- staff
- minutes
- type
I then created a summarized table with the following:
TableA =
SUMMARIZECOLUMNS (
'meetings'[staff]
, 'meetings'[type]
, "SumMinutesByStaffAndType", SUM( 'meetings'[minutes] )
)
This makes a pivot table with staff as rows and columns as types.
For this pivottable I need to calculate each cell as a percent of the column total. For each staff I need the average of their percents. There are only 5 meeting types so I need the sum of these percents divided by 5.
I don't know how to divide one number grouped by two columns by another number grouped by one column. I'm coming from the SQL world so my DAX is terrible and I'm desperate for advice.
I tried creating another summarized table to get the sum of minutes for each type.
TableB =
SUMMARIZECOLUMNS (
'meetings'[type]
, "SumMinutesByType", SUM( 'meetings'[minutes] )
)
From there I want 'TableA'[SumMinutesByStaffAndType] / 'TableB'[SumMinutesByType].
TableC =
SUMMARIZECOLUMNS (
'TableA'[staff],
'TableB'[type],
DIVIDE ( 'TableA'[SumMinutesByType], 'TableB'[SumMinutesByType]
)
"A single value for column 'Minutes' in table 'Min by Staff-Contact' cannot be determined. This can happen when a measure formula refers to a column that contains many values without specifying an aggregation such as min, max, count, or sum to get a single result."
I keep arriving at this error which leads me to believe I'm not going about this the "Power BI way".
I have tried making measures and creating matrices on the reports view. I've tried using the group by feature in the Query Editor. I even tried both measures and aggregate tables. I'm likely overcomplicating it and way off the mark so any help is greatly appreciated.
Here's an example of what I'm trying to do.
## Input/First table
staff minutes type
--------- --------- -----------
Bill 5 TELEPHONE
Bill 10 FACE2FACE
Bill 5 INDIRECT
Bill 5 EMAIL
Bill 10 OTHER
Gary 10 TELEPHONE
Gary 5 EMAIL
Gary 5 OTHER
Madison 20 FACE2FACE
Madison 5 INDIRECT
Madison 15 EMAIL
Rob 5 FACE2FACE
Rob 5 INDIRECT
Rob 20 TELEPHONE
Rob 45 FACE2FACE
## Second table with SUM of minutes, Grand Total is column total.
Row Labels EMAIL FACE2FACE INDIRECT OTHER TELEPHONE
------------- ------- ----------- ---------- ------- -----------
Bill 5 10 5 10 5
Gary 5 5 10
Madison 15 20 5
Rob 50 5 20
Grand Total 25 80 15 15 35
## Third table where each of the above cells is divided by its column total.
Row Labels EMAIL FACE2FACE INDIRECT OTHER TELEPHONE
------------- ------- ----------- ------------- ------------- -------------
Bill 0.2 0.125 0.333333333 0.666666667 0.142857143
Gary 0.2 0 0 0.333333333 0.285714286
Madison 0.6 0.25 0.333333333 0 0
Rob 0 0.625 0.333333333 0 0.571428571
Grand Total 25 80 15 15 35
## Final table with the sum of the rows in the third table divided by 5.
staff AVERAGE
--------- -------------
Bill 29.35714286
Gary 16.38095238
Madison 23.66666667
Rob 30.5952381
Please let me know if I can clarify an aspect.

Answer 1

You can make use of the built in functions like %Row total in Power BI, Please find the snapshot below
If this is not what you are looking for, kindly let me know (I have used your Input table)