Florian,

just a hint for working with WHERE clauses.

The IB_Datasets have a SQLWhereItem property, which can be
changed in and only in the OnPrepareSQL event.

What I do if I only want to change the WHERE clause  is with

DatasetPrepareSQL:

  SQLWhereItems.clear;

[If Condition1 then]

     SQLWhereItems.add(‘Column1 = :Param1’  or ‘Column1 = Value);

  [If Condition2]

  SQLWhereItems.add(‘Column2 = :Param2’)  and so on.

By default the SQLWhereItems are ANDED together (see IBO-Help)
but can ORED as well (in some recent versions IBO however had a
bug in building ORED selections itself.  If I need ORED selections I
build them myself as a single string).

If you are using Params, values can then be assigned in the

AfterPrepare Event:

DatasetAfterPrepare:

  P := Dataset.FindParam(‘Param1’);

  If Assigned(p) then

    p.Value (AsInteger, AsString …)  := Value;

In my experience this technique is very versatile. You can be sure that
only the WHERE clause is changed and the rest of your SQL text not
touched at all.

Rebuilding the WHERE clause would be triggered for example in your

components OnChange event:

SearchBoxOnChange:

  Dataset.InvalidateSQL;

  Dataset.Refresh;    

Herbert