TO_DATE IN ORACLE - Online Tech Support

This online tutorial page is based on examples to be easier to follow. The Oracle To_Date function converts data types like string of CHAR, VARCHAR2, NCHAR, or NVARCHAR2 to a DATE data type and this way you will be able to do date operations. You can leave the date format away if your date value in string has written in default database date format. Also NLS_DATE_FORMAT is optional but it gives you an opportunity to export the date value in another time region look. The Oracle To_Date syntax is following:

TO_DATE (<string>[,<date_format>] [,NLS_DATE_FORMAT]);

The first example has date November 20th 2010 in string as “2010/11/20” and behind it we have declared the Oracle date format that describes the date value look. Online Tech Support recommends to use always the date format even it is optional. Using a date format your date value will be converted always correctly and the default database date format can be changed without affecting any code.

 SELECT TO_DATE ('2010/11/20','yyyy/mm/dd') AS my_date
   FROM dual;

The second example with Oracle To_Date is using the same date value as above only with different format. The example above had number of years then months and in the last days but the following example has first number months then days and to last comes years. Also take a look at the date format it has changed among of the date value and reflects the date structure.

 SELECT to_date ('11/20/2010','mm/dd/yyyy') AS my_date
   FROM dual;

We have been using “/“-characters to separate date numbers on the last two examples above but using them is not obligated and the next example shows that the date value can contain only numbers. The value will be converted correctly while the date format is declared to reflect the value. Take a look at the output below the date has still remained to November 20th 2010.

 SELECT to_date ('20112010','ddmmyyyy') AS my_date
   FROM dual;

The Oracle To_Date function is so flexible that you can leave away even some date values. The fourth example has only month and year numbers declared and once again the date format allows the To_Date function to do conversion correctly. Since the day number is missing the date will become first day of month and the output has November 1st 2010.

 SELECT to_date ('11/2010','mm/yyyy') AS my_date
   FROM dual;

To convert a string to date type using only a year number is described on the following example above. The last example had no day number and the Oracle database took the first number of declared month but leaving away the month number you will receive the current month and not the first month of year as you may guessed. The example above has two columns where the first is converted date using year 2010 number and the second column has current date the April 15th 2011. Now have a look at the converted column “MY_DATE” the date is April 1st 2010.

 SELECT to_date ('2010','yyyy') AS my_date, SYSDATE
   FROM dual;

Oracle Date and Time Format Elements

Element	*TO_ datetime functions?**	Description
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. 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). 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: Additional discussion on this format model modifier in the Oracle Database SQL Language 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 Language Reference
HH HH12	Yes	Hour of day (1-12).
HH24	Yes	Hour of day (0-23).
IW		Week of year (1-52 or 1-53) based on the ISO standard.
IYY IY I		Last 3, 2, or 1 digit(s) of ISO year.
IYYY		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.
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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