Oracle to_char的时间数据格式转换

Oracle to_char的一些功能记录。
1、转成年月日时分秒的操作；
2、转成微妙的操作
SQL> select to_char(systimestamp, 'yyyy-mm-dd-hh24:mi:ss.ff') from dual;

TO_CHAR(SYSTIMESTAMP,'YYYY-MM-
------------------------------
2013-09-26-16:08:04.234000

注意，没有转成毫秒的参数格式。

如果需要转成毫秒，这样操作

SQL> select to_char(systimestamp, 'yyyy-mm-dd-hh24:mi:ss.ff3') from dual;

TO_CHAR(SYSTIMESTAMP,'YYYY-MM-
------------------------------
2013-09-26-16:12:10.640

3、转成零点到当前时间的秒数
SQL> select to_char(systimestamp, 'yyyymmddhh24miss -- SSSSS') from dual;

TO_CHAR(SYSTIMESTAMP,'YYYYMMDD
------------------------------
20130926160938 -- 58178

SQL> select to_char(systimestamp, 'yyyy-mm-dd-hh24:mi:ss'),

  2         to_char(systimestamp, 'yyyymmddhh24miss -- SSSSS'),
  3         to_char(systimestamp, 'hh24') * 60 * 60 +
  4         to_char(systimestamp, 'mi') * 60 + to_char(systimestamp, 'ss') +
  5         to_number(to_char(systimestamp, 'ff') / 1000000.00)
  6    from dual
  7  /

TO_CHAR(SYSTIMESTAMP,'YYYY-MM- TO_CHAR(SYSTIMESTAMP,'YYYYMMDD TO_CHAR(SYSTIMESTAMP,'HH24')*6
------------------------------ ------------------------------ ------------------------------
2013-09-26-16:00:13            20130926160013 -- 57613                                 57613

其他参数如下表所示：

Parameter Explanation
YEAR  Year, spelled out
YYYY  4-digit year
YYY
YY
Y  Last 3, 2, or 1 digit(s) of year.
IYY
IY
I  Last 3, 2, or 1 digit(s) of ISO year.
IYYY  4-digit year based on the ISO standard
Q  Quarter of year (1, 2, 3, 4; JAN-MAR = 1).
MM  Month (01-12; JAN = 01).
MON  Abbreviated name of month.
MONTH  Name of month, padded with blanks to length of 9 characters.
RM  Roman numeral month (I-XII; JAN = I).
WW  Week of year (1-53) where week 1 starts on the first day of the year and continues to the seventh day of the year.
W  Week of month (1-5) where week 1 starts on the first day of the month and ends on the seventh.
IW  Week of year (1-52 or 1-53) based on the ISO standard.
D  Day of week (1-7).
DAY  Name of day.
DD  Day of month (1-31).
DDD  Day of year (1-366).
DY  Abbreviated name of day.
J  Julian day; the number of days since January 1, 4712 BC.
HH  Hour of day (1-12).
HH12  Hour of day (1-12).
HH24  Hour of day (0-23).
MI  Minute (0-59).
SS  Second (0-59).
SSSSS  Seconds past midnight (0-86399).
FF  Fractional seconds.