字符集問題

1，查詢用戶信息如下（在字符集爲-字符編碼default）

SQL> select name from tab_a where product_id =1 and svc_id=0001 and status=2 and rownum<10;

NAME
--------------------------------------------------------------------------------
13820002750
13820653172
15122618002
13803024299
13820900227
13821206440
13920120914
？？？
13920076891

9 rows selected.

2，修改字符集在UTF-8下

NAME
--------------------------------------------------------------------------------
13820002750
13820653172
15122618002
13803024299
13820900227
13821206440
13920120914
13920076891

9 rows selected.

SQL>

很奇怪呢？