数据库查询输出的问题

Question

源程序如下       query1.Close;
       query1.sql.Clear;
       query1.sql.Add('select 明细单编号,机器型号,客户名称,出库单日期,软件cpu号,软件rom号,硬件版本 from HDR明细档案.db');
       query1.sql.Add('where 机器型号=:name and 出库单日期>:date1 and 出库单日期<:date2 order by 出库单日期');
       query1.Prepare;
       query1.Params[0].AsString:=trim(AdvComboBox_jqxh.Text);
       query1.Params[1].AsDate:=DateTimePicker1.Date;
       query1.Params[2].AsDate:=DateTimePicker2.Date;
       query1.Open;可是总是查询不到记录

Answer 1

trim(AdvComboBox_jqxh.Text):=query1.Params[0].AsString;是不是应该这样付值啊！！！！

Answer 2

query1.Params[1].AsString:=''''+DateTimeToString(DateTimePicker1.Date)+'''';
       query1.Params[2].AsString:=''''+DateTimeToString(DateTimePicker1.Date)+'''';