> The question was arise since I only change the SQL from
> 'SELECT * FROM SalesCall' to 'SELECT * FROM SalesCall
> WHERE ......' and putting some variable initialization,
> and the report doesn't work anymore.

Check that IBOQuery.CallbackInc = -1 (which I believe is the default
to TIBOQuery anway). Also check that you do not have other controls
attached to the dataset/datasource while reporting - and least during
experimentation.

Remember that NULL is a state and not a value, so NULL date values
will not be included in a range selection. You would explicitly have
to include an "OR MYDATE IS NULL" clause.

Run the SQLMonitor dialog, it may help show if there are any apparent
differences in what is happening in the report versus what is
happening on a grid.

Geoff Worboys
Telesis Computing