DAX DIVIDE function/expression with one column?

[Jam1]

Hello,

I am new to power BI DAX constructs and would like some help.  Task is to simply divide items within a single column.  Is this possibe?  For example - given the grid below, take New lable total purchases for Jan (west region) and divide by new label total purchases for Jan (total region) * 100 to get percentage.  Essentially, (3148 / 33888) * 100 = 9.3%.  All of the documentation that I've come across requires division to be taken place with two seperate columns.  Can you advise on how to express this calculation with the appropriate DAX formula?  I greatly appreciate the assist.

label	Month-of-Purchase	Region	PurchaseWk	Total Puchase
New	Jan	West	2015W02	3148
New	Feb	East	2015W05	7195
Moderate	Dec	South	2015W49	1882
Old	Mar	North	2015W15	2779
Old	Mar	Total Region	2015W15	15999
New	Jan	Total Region	2015W05	33888
Moderate	Dec	Total Region	2016W49	44444

Thanks!

[th3h0bb5 · Accepted solution]

I think your best bet is going to be to clean your data. As a general rule, you shouldn't have values and aggregated totals in the same column. If you took out the Totals from that column, you could use this DAX:

column= [Total Purchase] / SUM([Total Purchase]) *100

If you're unable to clean the data, I suggest trying the CALCULATE function (click here to read more).

[Jam1]

Agreed.  Best bet certainly looks like cleaning the data.  Thanks a ton!