FB

Oracle TO_DATEThe Oracle TO_DATE function is one of the most common and useful string manipulation functions in Oracle, but it can be confusing.

I’ll explain how to use the TO_DATE function in this article.

Purpose of the Oracle TO_DATE Function

The purpose of the TO_DATE function in Oracle is to convert a character value to a date value.

In reality, it converts any value which has a data type of CHAR, VARCHAR2, NCHAR,  or NVARCHAR2 into a value which has the data type of DATE.

It doesn’t convert the value into any of the other datetime datatypes. To use TO_DATE with time in the destination value, you’ll need to use either TO_TIMESTAMP, TO_TIMESTAMP_TZ (timezone functions), TO_DSINTERVAL, or TO_YMINTERVAL (interval functions).

 

Syntax

The syntax of the Oracle TO_DATE function is:

TO_DATE( charvalue, [format_mask], [nls_date_language] )

 

Parameters

The parameters of the Oracle TO_DATE function are:

  • charvalue (mandatory): This is the character value, or string, to convert into a data type. This is the main input to the function and should be one of the string data types mentioned earlier.
  • format_mask (optional): This is the format of the input value (charvalue). This is used to determine how the charvalue is made up, especially for data formats which are all numbers.
  • nls_date_language (optional): This value is used to determine how the output value is displayed.

Get Your Free PDF: 9 Ways to Improve your Database Skills

Oracle SQL Function Cheat Sheet

Subscribe and get a PDF cheat sheet of all of the Oracle SQL functions and parameters for easy reference!

We won't send you spam. Unsubscribe at any time. Powered by ConvertKit

Oracle TO_DATE Format Mask

The Oracle TO_DATE function includes a “format mask”. The format mask is helpful as it allows you to specify what format the date value was provided in.

If, for example you have a charvalue of ’02/05/2017′, does this mean May 2nd or Feb 5th? The result of the Oracle TO_DATE function would depend on the format you specify, and may be obvious depending on what region you’re from.

To make it clear, we need to specify some values for the format mask as part of the Oracle TO_DATE function.

The possible values are:

Year

Parameter Explanation
YEAR Year, spelled out in full words
YYYY 4-digit year
YYY Last 3 digits of year
YY Last 2 digits of year
Y Last digit of year
IYY Last 3 digits of ISO year
IY Last 2 digits of ISO year
I Last digit of ISO year
IYYY 4-digit year, which is based on the ISO standard
RRRR This format accepts a 2-digit year, and returns a 4-digit year. If the provided value is between 0 and 49, it will return a year greater than or equal to 2000. If the provided value is between 50 and 99, it will return a year less than 2000

 

Month

Parameter Explanation
Q Quarter of year, from 1 to 4. JAN to MAR = 1
MM Month, from 01 to 12. JAN = 01
MON Abbreviated name of month.
MONTH Name of month, padded with blanks to length of 9 characters.
RM Roman numeral month, from I to XII. JAN = I.

 

Week

Parameter Explanation
WW Week of year, from 1 to 53. Week 1 starts on the first day of the year, and continues to the seventh day of the year.
W Week of month, from 1 to 5. Week 1 starts on the first day of the month and ends on the seventh.
IW Week of year, from 1 to 52 or 1 to 53, based on the ISO standard.

 

Day

Parameter Explanation
D Day of week, from 1 to 7.
DAY Name of day.
DD Day of month, from 1 to 31.
DDD Day of year, from 1 to 366.
DY Abbreviated name of day.
J Julian day, which is the number of days since January 1, 4712 BC.

 

Time

Parameter Explanation
HH Hour of day, from 1 to 12.
HH12 Hour of day, from 1 to 12.
HH24 Hour of day, from 0 to 23.
MI Minute, from 0 to 59
SS Second, from 0 to 59
SSSSS Seconds past midnight, from 0 to 86399.
FF Fractional seconds. This uses a value from 1 to 9 after FF, to indicate the number of digits in the fractional seconds (e.g. FF7)

 

Indicators

Parameter Explanation
AM, A.M., PM, or P.M. Meridian indicator
AD or A.D AD indicator
BC or B.C. BC indicator
TZD Daylight savings information
TZH Time zone hour.
TZM Time zone minute.
TZR Time zone region.

As you can see, TO_DATE with time and date is possible, and it depends on the value being supplied.

 

Oracle NLS_DATE_LANGUAGE Explanation

The NLS_DATE_LANGUAGE can be specified in the Oracle TO_DATE function to determine how the date is shown. As you may know, different regions show the same date in different ways:

  • China: yyyy-mm-dd
  • UK: dd/mm/yyyy
  • US: mm/dd/yyyy

To use the NLS_DATE_LANGUAGE as part of this function, you can use any language listed under Table A-1 on the Oracle Language page. Some examples are American, English, French, German, and Swedish.

 

Examples of the TO_DATE Function

Here are some examples of the TO_DATE function. I find that examples are the best way for me to learn about code, even with the explanation above.

Example 1 – Simple Query

This query is just a straight-forward TO_DATE query with no formats specified. It assumes the default format for your Oracle installation.

SELECT TO_DATE('16-OCT-2013') AS date_test
FROM DUAL;

Result:

DATE_TEST
16/OCT/13

Example 2 – With Format

This query shows the same date, but with the format specified.

SELECT TO_DATE('16-10-2013', 'DD-MM-YYYY') AS date_test
FROM DUAL;

Result:

DATE_TEST
16/OCT/13

Example 3 – Different Format

This query shows a date with a different format specified, in YYYY/MM/DD format.

SELECT TO_DATE('2013/10/14', 'YYYY/MM/DD') AS date_test
FROM DUAL;

Result:

DATE_TEST
13/OCT/13

Example 4 – Format with No Separators

This query shows a date with no separators for the values.

SELECT TO_DATE('20131012', 'YYYYMMDD') AS date_test
FROM DUAL;

Result:

DATE_TEST
12/OCT/13

Example 5 – Different Date

This query is a different date using a specific format.

SELECT TO_DATE('08-10-2013', 'DD-MM-YYYY') AS date_test
FROM DUAL;

Result:

DATE_TEST
08/OCT/13

 

Similar Functions

Some functions which are similar to the Oracle TO_DATE function are:

  • TO_CHAR – converts a value to a VARCHAR2 type
  • TO_NUMBER – converts a value to a NUMBER type
  • CAST – used for many types, including dates

You can find a full list of Oracle functions here.

 

Video

For an example of the Oracle TO_DATE function, watch the video here.

 

Get Your Free PDF: 9 Ways to Improve your Database Skills

Oracle SQL Function Cheat Sheet

Subscribe and get a PDF cheat sheet of all of the Oracle SQL functions and parameters for easy reference!

We won't send you spam. Unsubscribe at any time. Powered by ConvertKit

Image courtesy of digitalart / FreeDigitalPhotos.net

Oracle SQL Function Cheat Sheet

Subscribe and get a PDF cheat sheet of all of the Oracle SQL functions and parameters for easy reference!

We won't send you spam. Unsubscribe at any time. Powered by ConvertKit

Get Your FREE PDF: 9 Ways to Improve your Database Skills