Is there a specific time-period that you want to pull data for? In that case you can add either a "range" parameter for the start and end dates or a separated start date and end date parameter. You would then use these parameters in the Select Expert to filter on the dates. The formula in the Select Expert would look something like this:

Range Parameter
{MyTable.DateField} in {?Date Range Param}

Two date parameters
{MyTable.DateField} >= {?Start Date} and
{MyTable.DateField} <= {?End Date}

Note that sometimes the range parameter doesn't pull data that for the start date and/or end date - just the data between the two.

-Dell