1Z0-051-5题

5. Which SQL statements would display the value 1890.55 as $1,890.55? (Choose three .)
A. SELECT TO_CHAR(1890.55,'$0G000D00')  FROM DUAL;
B. SELECT TO_CHAR(1890.55,'$9,999V99')  FROM DUAL;
C. SELECT TO_CHAR(1890.55,'$99,999D99')  FROM DUAL;
D. SELECT TO_CHAR(1890.55,'$99G999D00')  FROM DUAL;
E. SELECT TO_CHAR(1890.55,'$99G999D99')  FROM DUAL;
Answer: ADE
答案解析：
A:

SQL> SELECT TO_CHAR(1890.55,'$0G000D00')  FROM DUAL;

TO_CHAR(18
----------
 $1,890.55

B：
SQL> SELECT TO_CHAR(1890.55,'$9,999V99')  FROM DUAL;

TO_CHAR(1
---------
 $1,89055

C：
SQL> SELECT TO_CHAR(1890.55,'$99,999D99')  FROM DUAL;
SELECT TO_CHAR(1890.55,'$99,999D99')  FROM DUAL
                       *
ERROR at line 1:
ORA-01481: invalid number format model

D：
SQL> SELECT TO_CHAR(1890.55,'$99G999D00')  FROM DUAL;

TO_CHAR(189
-----------
  $1,890.55

E：
SQL> SELECT TO_CHAR(1890.55,'$99G999D99')  FROM DUAL;

TO_CHAR(189
-----------
  $1,890.55

G表示分组分隔符group
D表示小数点decimal point
V表示移动N位（小数点），乘以10的n次方后面跟几位就是几次方。
","和G或者D不能同时出现，如果把C答案的D改成“.”，也正确

SQL> SELECT TO_CHAR(1890.55,'$99,999.99') FROM DUAL;

TO_CHAR(189
-----------
  $1,890.55
总之，字符和字母不能同时出现。