关于一个oracle函数的问题?

Question

select to_char(a) from a;

Answer 1

select to_char(a) from A

Answer 2

12:38:52 SQL> select to_char(123.123) from dual;TO_CHAR
-------
123.123实际：100
12:39:03 SQL> select to_char(123.123,9999.9) from dual;TO_CHAR
-------
  123.1实际：30
12:39:21 SQL> select to_char(123.123,9999.99999) from dual;TO_CHAR(123
-----------
  123.12300实际：30
12:39:33 SQL>

Answer 3

补充：
SQL> select to_char(123) from dual;TO_CHAR(123)
------------
123

Answer 4

你写的很对啊
Select TO_char(a) From A

Answer 5

select to_char(a) from a;