with datamodule1.ClientDataSet1 do
begin
close;
CommandText:='select ckysmxb.clbhid,jzbhid,clmc,clgg,cldw,rksl from ckysmxb '+
' left join [clxm] on ckysmxb.clbhid=clxm.clbhid '+
' where ckysmxb.ckysid=:ckysid order by ckysmxb.clbhid desc';

Params.ParamValues['ckysid']:=trim(combobox3.items[combobox3.ItemIndex]);
//showmessage(quotedstr(trim(combobox3.items[combobox3.ItemIndex])));
open;

执行这条语句时有时候报错(偶尔):(当我来回切换combox3上的item时)
"不能比较和排序text,ntext和Image类型，除非使用IS NULL或Like运算符"

请问如何解决?(每次设置断点过后它就不出错了,想让我找不到它)