执行修改时关键字 'and' 附近有语法错误.

执行修改时关键字 'and' 附近有语法错误.
private string GET_RJZZQXX = "select * from rxzzqxx";
private string CHECK_RJZZQXX = "select rjzzqID,owner,softname,catagory,sydw,softnumber,djsj,otherowner from rxzzqxx where rjzzqID=@rjzzqID and owner=@owner and softname=@softname and catagory=@catagory and sydw=@sydw and softnumber=@softnumber and djsj=@djsj and otherowner=@otherowner";
private const string ADD_RJZZQXX = "insert into rxzzqxx(rjzzqID,owner,softname,catagory,sydw,softnumber,djsj,otherowner) values(@rjzzqID,@owner,@softname,@catagory,@sydw,@softnumber,@djsj,@otherowner)";
private const string DEL_RJZZQXX = "delete from rxzzqxx where rjzzqID=@rjzzqID";
private const string MOD_RJZZQXX = "update rxzzqxx set owner=@owner and softname=@softname and catagory=@catagory and sydw=@sydw and softnumber=@softnumber and djsj=@djsj and otherowner=@otherowner where rjzzqID=@rjzzqID";
private const string QUERY_RJZZQXX = "select * from rxzzqxx where ";
private const string QUER_LIST = "select * from rxzzqxx";
private const string QUER_LIST_TEXTBOX = "select * from rxzzqxx where rjzzqID=";
值不能为 null.
参数名:control if (Modify.modifyuser(rjzzqID,owner,softname,catagory,sydw,softnumber,djsj,otherowner))
{
ScriptManager.RegisterStartupScript(UpdatePanel2,this.GetType(),"updateScript","alert('修改成功!')",true);
SELECT();
}值不能为 null.
参数名:control