declare
  cursor my_cur is
    select  t.rowid row_id,t.ID1,t.NUM1
    from table1 t
    order by 1;
  v_count number;
  v_j  number;
  v_pid number;
begin
  v_count:=0;
  v_j:=1;
  v_pid:=0;
  for row_t in my_cur loop
    if (v_pid=row_t.NUM1) then 
    begin
       update table1 set NUM2=v_j
         where rowid=row_t.row_id; 
    end;
      else 
       begin
          v_j:=v_j+1;
          update table1 set NUM2=v_j
           where rowid=row_t.row_id;
           v_pid:=row_t.NUM1;
       end;
     end if;  
    v_count:=v_count+1;
    if (v_count>=2000) then
      commit;
      v_count:=0;
    end if;
  end loop;
  commit;
end;
/

------解决方案--------------------
cursor myCur is select * from test;
oneRow test%rowtype;
flag1 number;
flag2 number;
flag3 number;
begin
flag1:=0;
flag2:=-1;
flag3:=0;
open myCur;
fetch myCur into oneRow;
while(myCur%found)
loop
if flag2=-1 then
select num1 into flag2 from test where id=oneRow.id;
flag1:=flag1+1;
UPDATE test set num2=flag1 where id=oneRow.id;
else
select num1 into flag3 from test where id=oneRow.id;
if flag3<>flag2 then
flag1:=flag1+1;
end if;
flag2:=flag3;
UPDATE test set num2=flag1 where id=oneRow.id;
end if;
fetch myCur into oneRow;
end loop;
close myCur;

------解决方案--------------------
探讨

我自己搞的一个，

大侠批评一下吧。

create table test(id1 int, num1 int);

insert into test values(1,0);
insert into test values(2,0);
insert into test values(3,0);
insert into test values(4,1);
insert into……