ＤＥＬＰＨＩ循环语句从字符到日期的转换

Question

我的数据表T1内有字段chno  char(12)  
内有数据
         chno        dateno   
        031108       2003-11-08
        031101       2003-11-01
        031110       2003-11-00
        031111       2003-11-11
        031111       2003-11-11
我要一次性把它转成日期型的，格式：2003-11-08       请各位帮忙分别用ＤＥＬＰＨＩ循环语句一次性把我所有的数据从表t1内的以chno char(12)转到另一个字段dateno  datetime内

Answer 1

var
  I:integer;
  astr:string;
begin
For I:=0 to table.recoredcount-1 do
begin
  astr:=fieldbyname(chno).asstring;
  fieldbyname('dateno').value:=strtodate('20'+astr[1]+astr[2]+'-'+astr[3]+astr[4]+'-'+astr[5]+astr[6]);
  post;
  next;
end;
end;

Answer 2

function chno_dateno(value:string): tdatetime;
 var
   bl: Tdatetime;
   fyear, fmonth, fday: word;
begin
   fyear:=strtoint('20'+copy(value,1,2));
   fmonth:=strtoint(copy(value,3,2));
   fday:=strtoint(copy(value,5,2));
   bl:=encodedate(fyear,fmonth,fday);
   result:=bl;
end;

Answer 3

select chno,convert(datetime,substring(chno,3,2)+'-'+substring(chno,5,2))+'-'+substring(chno,1,2) as dateno from table1//注意：‘月-日-年’