Oracleto_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 SQLgt; select to_char(systimestamp,

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

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其他参数如下表所示：

ParameterExplanation

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.

其他语言objective-c的date格式转换，参考