Gap-filling at the beginning of a TIMESERIES

Hi, I'm trying to generate some aggregate numbers grouped by date using the TIMESERIES clause to provide gap-filling. The gap-filling works, so long as data exists on the first and last day, but if it doesn't, the data will only start on the first day containing data. For example, consider the following query: SELECT slice_time FROM data_table WHERE data_date BETWEEN '2013-06-01' AND '2013-06-10' TIMESERIES slice_time AS '1 DAY' OVER (ORDER BY data_date); If there are no rows with data_date from '2013-06-01' to '2013-06-04' then the TIMESERIES will not be gap-filled for those dates. What can I do?