Oracle Conversion SRFs and Date Formatting

日期的轉換可參考下表

Table 2-15 Datetime Format Elements

Element	Specify in TO_* datetime functions?	Description
- / , . ; : "text"	Yes	Punctuation and quoted text is reproduced in the result.
AD A.D.	Yes	AD indicator with or without periods.
AM A.M.	Yes	Meridian indicator with or without periods.
BC B.C.	Yes	BC indicator with or without periods.
CC SCC	No	Century. If the last 2 digits of a 4-digit year are between 01 and 99 (inclusive), then the century is one greater than the first 2 digits of that year. If the last 2 digits of a 4-digit year are 00, then the century is the same as the first 2 digits of that year. For example, 2002 returns 21; 2000 returns 20.
D	Yes	Day of week (1-7).
DAY	Yes	Name of day, padded with blanks to display width of the widest name of day in the date language used for this element.
DD	Yes	Day of month (1-31).
DDD	Yes	Day of year (1-366).
DL	Yes	Returns a value in the long date format, which is an extension of Oracle Database's DATE format (the current value of the NLS_DATE_FORMAT parameter). Makes the appearance of the date components (day name, month number, and so forth) depend on the NLS_TERRITORY and NLS_LANGUAGE parameters. For example, in the AMERICAN_AMERICA locale, this is equivalent to specifying the format 'fmDay, Month dd, yyyy'. In the GERMAN_GERMANY locale, it is equivalent to specifying the format 'fmDay, dd. Month yyyy'. Restriction: You can specify this format only with the TS element, separated by white space.
DS	Yes	Returns a value in the short date format. Makes the appearance of the date components (day name, month number, and so forth) depend on the NLS_TERRITORY and NLS_LANGUAGE parameters. For example, in the AMERICAN_AMERICA locale, this is equivalent to specifying the format 'MM/DD/RRRR'. In the ENGLISH_UNITED_KINGDOM locale, it is equivalent to specifying the format 'DD/MM/RRRR'. Restriction: You can specify this format only with the TS element, separated by white space.
DY	Yes	Abbreviated name of day.
E	No	Abbreviated era name (Japanese Imperial, ROC Official, and Thai Buddha calendars).
EE	No	Full era name (Japanese Imperial, ROC Official, and Thai Buddha calendars).
FF [1..9]	Yes	Fractional seconds; no radix character is printed (use the X format element to add the radix character). Use the numbers 1 to 9 after FF to specify the number of digits in the fractional second portion of the datetime value returned. If you do not specify a digit, then Oracle Database uses the precision specified for the datetime datatype or the datatype's default precision. Examples: 'HH:MI:SS.FF' SELECT TO_CHAR(SYSTIMESTAMP, 'SS.FF3') from dual;
FM	Yes	Returns a value with no leading or trailing blanks. See Also: Additional discussion on this format model modifier in the Oracle Database SQL Reference
FX	Yes	Requires exact matching between the character data and the format model. See Also: Additional discussion on this format model modifier in the Oracle Database SQL Reference
HH	Yes	Hour of day (1-12).
HH12	No	Hour of day (1-12).
HH24	Yes	Hour of day (0-23).
IW	No	Week of year (1-52 or 1-53) based on the ISO standard.
IYY IY I	No	Last 3, 2, or 1 digit(s) of ISO year.
IYYY	No	4-digit year based on the ISO standard.
J	Yes	Julian day; the number of days since January 1, 4712 BC. Number specified with J must be integers.
MI	Yes	Minute (0-59).
MM	Yes	Month (01-12; January = 01).
MON	Yes	Abbreviated name of month.
MONTH	Yes	Name of month, padded with blanks to display width of the widest name of month in the date language used for this element.
PM P.M.	No	Meridian indicator with or without periods.
Q	No	Quarter of year (1, 2, 3, 4; January - March = 1).
RM	Yes	Roman numeral month (I-XII; January = I).
RR	Yes	Lets you store 20th century dates in the 21st century using only two digits. See Also: Additional discussion on RR datetime format element in the Oracle Database SQL Reference
RRRR	Yes	Round year. Accepts either 4-digit or 2-digit input. If 2-digit, provides the same return as RR. If you do not want this functionality, then enter the 4-digit year.
SS	Yes	Second (0-59).
SSSSS	Yes	Seconds past midnight (0-86399).
TS	Yes	Returns a value in the short time format. Makes the appearance of the time components (hour, minutes, and so forth) depend on the NLS_TERRITORY and NLS_LANGUAGE initialization parameters. Restriction: You can specify this format only with the DL or DS element, separated by white space.
TZD	Yes	Daylight savings information. The TZD value is an abbreviated time zone string with daylight savings information. It must correspond with the region specified in TZR. Example: PST (for US/Pacific standard time); PDT (for US/Pacific daylight time).
TZH	Yes	Time zone hour. (See TZM format element.) Example: 'HH:MI:SS.FFTZH:TZM'.
TZM	Yes	Time zone minute. (See TZH format element.) Example: 'HH:MI:SS.FFTZH:TZM'.
TZR	Yes	Time zone region information. The value must be one of the time zone regions supported in the database. Example: US/Pacific
WW	No	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	No	Week of month (1-5) where week 1 starts on the first day of the month and ends on the seventh.
X	Yes	Local radix character. Example: 'HH:MI:SSXFF'.
Y,YYY	Yes	Year with comma in this position.
YEAR SYEAR	No	Year, spelled out; S prefixes BC dates with a minus sign (-).
YYYY SYYYY	Yes	4-digit year; S prefixes BC dates with a minus sign.
YYY YY Y	Yes	Last 3, 2, or 1 digit(s) of year.

 

SELECT to_char(sysdate, 'mm-dd-yyyy') from dual

TO_CHAR(SYSDATE,'MM-DD-YYYY')
02-22-2022

SELECT to_char(sysdate, 'ddth "of" month, yyyy') from dual

TO_CHAR(SYSDATE,'DDTH"OF"MONTH,YYYY')
22nd of 2月 , 2022

數字的格式可以參考下表

Table 2-13 Number Format Elements

Element	Example	Description
, (comma)	9,999	Returns a comma in the specified position. You can specify multiple commas in a number format model. Restrictions: A comma element cannot begin a number format model. A comma cannot appear to the right of a decimal character or period in a number format model.
. (period)	99.99	Returns a decimal point, which is a period (.) in the specified position. Restriction: You can specify only one period in a number format model.
$	$9999	Returns value with a leading dollar sign.
0	0999 9990	Returns leading zeros. Returns trailing zeros.
9	9999	Returns value with the specified number of digits with a leading space if positive or with a leading minus if negative. Leading zeros are blank, except for a zero value, which returns a zero for the integer part of the fixed-point number.