if you are joining straight to the tables in the database (not using a stored proc or view) and you don't have a table of just dates, you can't show the 0...CR needs to see the data, it only reports on teh data that it sees.
If the values are known ahead of time, then you can have counters for each value and display those in teh group footer (which makes the above statement incorrect, but I thought that it was pertaining to showing days that have no info).
shared variables would be the way to go, or running totals, for each variable that you are tracking. You can't create columns from the data...but if you have a formula you can have each formula (or running total probably) act as a column.
a clearer example might help more