How do you declare a variable inside a Teradata macro?

There is no facility to declare variables inside a Teradata macro. You can, however, pass values into the macro by means of input parameters. These values will then be embedded in the SQL statements that the macro contains. Teradata stored procedures, on the other hand, support IN, OUT and INOUT parameters, as well as the ability to declare variables within the procedure itself. Such variables could be useful as counters when you have looping logic, for example.