DBGridEh问题求助

Delphi(Pascal) code

procedure TForm2.DBGridEh1CellClick(Column: TColumnEh);
var
  rq:string;
begin
  rq:=formatdatetime('yyyy-MM-dd HH:mm:ss',now());
  with adoquery3 do
    begin
     close;
     sql.Clear;
     sql.Add('update Happy_SaleRecord set Received=1,Payed=1,ReceiveDate='+''''+rq+''''' where UserCode='+''''+dbtext1.Field.AsString+'''');
     open;
  end;
end;

代码如上 为什么已选择就出错呢

procedure TForm2.DBGridEh1CellClick(Column: TColumnEh);
var
  rq:string;
begin
  rq:=formatdatetime('yyyy-MM-dd HH:mm:ss',now());
  with adoquery3 do
  begin
  close;
  sql.Clear;
  sql.Add('update Happy_SaleRecord set Received=1,Payed=1,ReceiveDate='''+rq+''' where UserCode='''+dbtext1.Field.AsString+''' ');
  ExecSql;
  end; 
end;