If you tried something like:
with cds1.Params do begin ParamByName('finish').AsDateTime := now;Â Â Â ParamByName('start').AsDateTime := Now-1;Â Â end; cds1.Open
And you received error like: DBX Error - ParameterNotSet then don't use AsDateTime, use AsSQLTimeStamp := DateTimeToSQLTimeStamp(Now-1);, so your code should look like:
with cds1.Params do begin ParamByName('finish').AsSQLTimeStamp := DateTimeToSQLTimeStamp(now);   ParamByName('start').AsDateTime := DateTimeToSQLTimeStamp(Now-1);  end; cds1.Open