Macro variables are the most essential part of the SAS macro facility. One can create macro variables by using the %LET statement, the SYMPUT routine, or the INTO clause in the SELECT statement from the SQL procedure. Sometimes a SAS programmer is often unsure when best to use which method due to a lack in understanding each step of macro language processing. This lack in understanding includes how SAS statements are transferred from the input stack to the macro processor and DATA step compiler, what role the macro processor plays during this process, and when best to utilize the interface to interact with the macro facility during the DATA or SQL execution. Once one grasps the intricacies of macro language processing, one will best know how to accurately create a macro variable.