Using the TO_CHAR Function with Dates
TO_CHAR converts a datetime data type to a value of VARCHAR2 data type in the format specified by the format_model. A format model is a character literal that describes the format of datetime stored in a character string. For example, the datetime format model for the string '11-Nov-1999' is 'DD-Mon-YYYY'. You can use the TO_CHAR function to convert a date from its default format to the one that you specify.
Guidelines
* The format model must be enclosed with single quotation marks and is case-sensitive.
* The format model can include any valid date format element. But be sure to separate the date value from the format model with a comma.
* The names of days and months in the output are automatically padded with blanks.
* To remove padded blanks or to suppress leading zeros, use the fill mode fm element.
Elements of the Date Format Model
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DY Three-letter abbreviation of the day of the week
DAY Full name of the day of the week
DD Numeric day of the month
MM Two-digit value for the month
MON Three-letter abbreviation of the month
MONTH Full name of the month
YYYY Full year in numbers
YEAR Year spelled out (in English)