NLS_CALENDAR

Property	Description
Parameter type	String
Syntax	`NLS_CALENDAR = "calendar_system"`
Default value	None, implies `GREGORIAN`
Modifiable	`ALTER SESSION`
Range of values	Any valid calendar format name
Basic	No

NLS_CALENDAR specifies which calendar system Oracle uses. It can have one of the following values:

Arabic Hijrah
English Hijrah
Gregorian
Japanese Imperial
Persian
ROC Official (Republic of China)
Thai Buddha

For example, suppose NLS_CALENDAR is set to "Japanese Imperial", the date format is "E YY-MM-DD". ("E" is the date format element for the abbreviated era name.) If the date is May 15, 1997, then the SYSDATE is displayed as follows:

SELECT SYSDATE FROM DUAL;
SYSDATE
--------
H 09-05-15

Note:

The value of the initialization parameter NLS_CALENDER is used to initialize the session value of this parameter, which is the actual value referenced by the SQL query processing. If the initialization parameter is not specified, the initial session value becomes GREGORIAN. This initial value is overridden by a client-side value if the client is OCI-based and the NLS_LANG client setting (environment variable) is defined.