procedure TForm1.DBGrid1TitleClick(Column: TColumn);
var
st:ZAbstractRODataset.TSortType;
begin
st:=ZReadOnlyQuery1.SortType;
ZReadOnlyQuery1.SortedFields:=Column.FieldName;
If st = stAscending then ZReadOnlyQuery1.SortType:=stDescending else ZReadOnlyQuery1.SortType:=stAscending;
DataSource1.DataSet.First;
end;
@bummi thank you