Query2.Close;
Query2.SQL.Clear;
Query2.SQL.Add('select * from examenes where fechaexamen between :F1 And :F2');
Query2.Parameters.ParamByName('F1').AsDate:= DateEdit1.Date;
Query2.Parameters.ParamByName('F2').AsDate:= DateEdit2.Date;
Query2.Open;
O esta otra
Query2.Close;
Query2.SQL.Clear;
Query2.SQL.Add('select * from examenes where fechaexamen between :#F1# And :#F2#');
Query2.Parameters.ParamByName('F1').Value:= DateEdit1.Date;
Query2.Parameters.ParamByName('F2').Value:= DateEdit2.Date;
Query2.Open;