sql.add('ORDER BY 日期 ASC ')加上这句后，我程序中DBNavigator1的删除接钮变灰了?

[cm]

if (form1.table1.FieldByName(combobox1.Text).AsString=edit5.Text )
then
begin
with query1 do
begin
close;
sql.clear;
sql.add('Select * From "db\show.db" As show');
sql.add('where 署名 between :date1 and :date2 ');
parambyname('date1').Value:=ComboBox1.text;//strtodate(datetostr(DateTimePicker1.Date));
parambyname('date2').Value:=ComboBox1.text;
？？？？？ sql.add('ORDER BY 日期 ASC ');
open;
last;
end;
是open与active ,execsql有冲突吗