You may want to explore the SAS DATA STEP functions INTCK and also INTNX; the latter function can be helpful with generating DATE and DATETIME variable values, based on other variables. For example, you can use a DATA STEP DO/END loop to generate (OUTPUT) SAS observations for each date value in a date-range, say for the past 12 months or 26 weeks.
Scott Barry
SBBWorks, Inc.