Help with DAX code to subtract previous row

[Anonymous]

I need help to create DAX code to subtract previous row in SMU column. - refer table below.

For example 682-0=0, 895-682=213,910-895=15,950-910=40,1682-950=732. 

Any assistance would be greatly appreciated thank you. 

[amitchandak · Accepted solution]

@Anonymous , Try a new column like

Diff =[SMU] - maxx(filter(Table, [machine_no] =earlier([Machine_no]) && [SMU] < earlier([SMU])),[SMU])