Oracle中to_char的使用

to_char (for dates)

看测试：

SQL> SELECT TO_CHAR(SYSDATE,'yyyy-MM-dd HH24:MI:ss') FROM DUAL;                                                 

2012-07-19 17:35:49    

SQL> SELECT TO_CHAR (SYSDATE,'D') FROM DUAL;  （Ｄ一个星期的第几天）                                                                   

5                                                                              

SQL> SELECT TO_CHAR (SYSDATE,'day') FROM DUAL;　（day 一个星期的星期几）

星期四                                                                         

SQL> SELECT TO_CHAR (SYSDATE,'yyyy') FROM DUAL;　（yyyy四位的年）

2012                                                                           

SQL> SELECT TO_CHAR (SYSDATE,'yyy') FROM DUAL;　 （yyy三位的年）

012                                                                             

SQL> SELECT TO_CHAR (SYSDATE,'mm') FROM DUAL;　　（mm当前月）

07                                                                             

SQL> SELECT TO_CHAR (SYSDATE,'dd') FROM DUAL;　　（dd 当前月的多少日）

19                                                                              

SQL> SELECT TO_CHAR (SYSDATE,'ddd') FROM DUAL;  (ddd 一年的第多少天)

201                                                                            

SQL> SELECT TO_CHAR (SYSDATE,'hh') FROM DUAL;　（hh　当前时间的小时）

05                                                                              

SQL> SELECT TO_CHAR (SYSDATE,'hh24') FROM DUAL;（hh24　当前时间的小时）

17                                                                             

SQL> SELECT TO_CHAR (SYSDATE,'mi') FROM DUAL;　（mi　当前时间的分钟）

30                                                                             

SQL> SELECT TO_CHAR (SYSDATE,'ss') FROM DUAL;　（ss当前时间的秒）

53                                                                             

SQL> SELECT TO_CHAR (SYSDATE,'mon') FROM DUAL;　（简写的月）

7月                                                                            

SQL> SELECT TO_CHAR (SYSDATE,'month') FROM DUAL;　（大写的月）                                                                   

7月                                                                             

SQL> SELECT TO_CHAR (SYSDATE,'ww') FROM DUAL;　　（今年的第多少周）

29                                                                             

SQL> SELECT TO_CHAR (SYSDATE,'w') FROM DUAL;　（这个月的第多少周）

3                                                                               

SQL> SELECT TO_CHAR (SYSDATE,'q') FROM DUAL;　　（今年的哪个季度）

3                                                                              

SQL> SELECT TO_CHAR (SYSDATE,'rm') FROM DUAL;                

vii                                                                            

SQL> SELECT TO_CHAR (SYSDATE,'j') FROM DUAL;                                                           

2456128                                                                         

SQL> SELECT TO_CHAR (SYSDATE,'sssss') FROM DUAL;  （sssss　毫秒）                                                               

63234                                                                          

SQL> SELECT TO_CHAR (SYSDATE,'ss') FROM DUAL;　（ss　秒）                                                                   

02