Subtracting two columns

[Anonymous]

Hello Community, 

I have two columns that have the following categories: 

Station	Scene Station
52	52
63	63
61	61
24	24
11	11
103	103
	Mutual Aid
	12C
blanks	blanks

When I sum the count distict of my incident ID for each category, I get the following distribution: 

I would like to substract the count district of incident ID for 'Station' by count district of incident ID for ' Scene Station', would anyone know how to do this?

Thank you for the help, 

Denisse

[amitchandak]

@Anonymous , You need to create a common table, join to both columns, and use userelation. Please find the attached after signature