What is the best way to implement rolling time dimensions based on current day or current month in Analysis Services? I can use LastPeriods to get the previous 30 days or 12 months, but what would the MDX code be to get the current date member from the cube to start out with? We do this in Essbase currently with a Substitution Variable. We use a SQL Server script to set the Current Day or Current Month variable in the cube, then choose that in the browser as our starting point and then choose a set number of previous periods. I am trying to convert some Essbase cubes to Analysis Services and this is the only thing I haven't figured out how to convert yet. The Essbase TBLast MDX equivalent was posted on this site and it works better than Essbase's TBLast. It would have taken me quite a while to figure it out on my own. Thanks for any suggestions.