Take another look at the table in the Different variable length and additional variables section. There are five variables in the output dataset. It would be helpful if we knew which observations came from the Customer_X or Customer_Y table. We will modify the program to create a Source variable that tells us which table has contributed to specific observations:
Data Customer;Set Customer_X (in = a) Customer_Y (in = b);If a = 1 then Source = "X";Else Source = "Y";Run;
This will give the following table as the resultant output:
The IN temporary variable is only available for the duration of the data step. However, ...