[Oracle] TO_DATE 날짜형 함수 사용하는 방법
오라클에서 날짜형 변환 함수인 TO_DATE는 다음과 같은 매개변수를 설정할 수 있습니다.
- 첫 번째 매개변수 => 날짜형으로 변경할 문자
- 두 번째 매개변수 => (선택 변수) 날짜형 포맷을 설정합니다. 생략하는 경우에는 기본 지역, 날짜 형식을 사용합니다. 'J'를 설정하면 쥴리안 일자(율리우스일)로 설정합니다.
- 세 번째 매개변수 => (선택 변수) NLS 매개변수를 지정합니다. NLS(National Language Support)는 'NLS_DATE_LANGUAGE = language' 형태로 사용합니다.
TO_DATE 날짜형 포맷 조회 방법
2번째 매개변수 관련 조회 방법은 다음과 같습니다.
SELECT *
FROM V$NLS_PARAMETERS
WHERE PARAMETER IN ('NLS_TERRITORY', 'NLS_DATE_FORMAT');
PARAMETER VALUE
---------------
NLS_TERRITORY KOREA
NLS_DATE_FORMAT RR/MM/DDTO_DATE 날짜형 데이트타임 포맷
날짜형 포맷 요소는 다음과 같습니다. 자주 사용하는 것으로는 YYYY, MM, DD, HH24, MI, HH, D, DAY, DY 등이 있습니다.
| Element | 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 | Century.
|
|
| D | Yes | Day of week (1-7). This element depends on the NLS territory of the session. |
DAY |
Yes | Name of day. |
| 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 the Oracle Database DATE format, determined by 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 | Yes | Abbreviated era name (Japanese Imperial, ROC Official, and Thai Buddha calendars). |
| EE | Yes | 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 data type or the data type's default precision. Valid in timestamp and interval formats, but not in DATE formats.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: FM |
| FX | Yes | Requires exact matching between the character data and the format model. See Also: FX |
| HH HH12 | Yes | Hour of day (1-12). |
| HH24 | Yes | Hour of day (0-23). |
| IW | Calendar week of year (1-52 or 1-53), as defined by the ISO 8601 standard.
|
|
| IYYY | 4-digit year of the year containing the calendar week, as defined by the ISO 8601 standard. | |
| IYY IY I | Last 3, 2, or 1 digit(s) of the year containing the calendar week, as defined by the ISO 8601 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. |
| PM P.M. | Yes | Meridian indicator with or without periods. |
| Q | 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: "The RR Datetime Format Element" |
| 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 saving information. The TZD value is an abbreviated time zone string with daylight saving information. It must correspond with the region specified in TZR. Valid in timestamp and interval formats, but not in DATE formats.Example: PST (for US/Pacific standard time); PDT (for US/Pacific daylight time). |
| TZH | Yes | Time zone hour. (See TZM format element.) Valid in timestamp and interval formats, but not in DATE formats.Example: 'HH:MI:SS.FFTZH:TZM'. |
| TZM | Yes | Time zone minute. (See TZH format element.) Valid in timestamp and interval formats, but not in DATE formats.Example: 'HH:MI:SS.FFTZH:TZM'. |
| TZR | Yes | Time zone region information. The value must be one of the time zone region names supported in the database. Valid in timestamp and interval formats, but not in DATE formats.Example: US/Pacific |
| 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. | |
| X | Yes | Local radix character. Example: 'HH:MI:SSXFF'. |
| Y,YYY | Yes | Year with comma in this position. |
| YEAR SYEAR | 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. |
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