delphi7中更新数据问题
procedure TForm1.Button1Click(Sender: TObject);
begin
ADOQuery1.Close;
ADOQuery1.SQL.Clear;
ADOQuery1.SQL.Add('Update huizong SET snum=:a+b+c');
ADOQuery1.SQL.Add('select * from huizong where snum is null');
ADOQuery1.ExecSQL;
end;
end.
为什么我一执行就会失败呢