Previous Transaction date DAX help

Hey,

here is an example for a calculated column using variable instead of the EARLIER function

Previous transaction date = 
var currentDate = 'yourTableName[Transaction date]
var currentCustomer = 'yourTableName'[Client]
var currentReseller = 'yourTableName'[Reseller]
var currentProduct = 'yourTableName'[Product]
return
CALCULATE(MAX('yourTableName'[Transaction date]),
    FILTER(ALL('yourTableName'),
        'yourTableName[Date] < currentDate
        && 'FactWithDates'[Customer] = currentCustomer
	&& 'yourTableName'[Reseller] = currentReseller
	&& 'yourTableName'[Product] = currentProduct
    )
)

• For each row the current values for Client, Reseller, and Product are stored in variables.
• CALCULATE is used to transform the existing ROWCONTEXT (we are creating a calculated column), into a FILTER CONTEXT
• The now existing FILTER CONTEXT  has to be expanded, to gain access to all records using FILTER(ALL('yourTableName), ...
• The rows are filter down using the variables
• The MAX transaction date is calculated, from all Transactions date that are smaller than the date of the variable

Hope this helps