See the attached. I used two calculated fields:
System Type Divisor has the formula:
IF [System Type] = 'CC' OR [System Type] = 'DD'
OR [System Type] = 'EE' THEN 3 ELSE 1 END
Adjusted Size has the formula:
ZN([Size])/[System Type Divisor]
Then in the view this is aggregated to the viz level of detail (vizLOD) which is based on the dimensions in the view. In a view with Make and System Type we get to see the details:
Then in a view with just make we get an accurate number total of Adjusted Size:
Tableau v9.3 workbook is attached. Let me know if you have any questions!
sumif for divisor.twbx 48.7 KB
Unfortunately this answer cannot reflect the desired information. For instance in the number of records column CC, DD and EE are recorded separately instead of once as a group. My problem is not the total size (at least for the moment) but the numbers of records of the systems. My data set is huge with a variety of attributes on each line and I have to apply multiple filters to a "clean" visualisation. What I made was a simple grouping of data as follows:
but I would like the number of records of the "Group" lines to be 1 instead of 3.
I will attach a workbook with updated calculated fileds.
sumif for divisor_new.twbx 70.1 KB