Date Data Types

The date data types that are supported are listed in Table 2-5, "OLAP DML Date Data Types".

Table 2-5 OLAP DML Date Data Types

Data Type	Data Value
`DATETIME`	Dates between January 1, 4712 B.C. and December 31, 9999 A.D., and times in hours, minutes and seconds.
`DATE`	Dates between January 1, 1000 A.D. and December 31, 9999 A.D.

A number of options determine how date and time values are handled. These options are listed in Table A-16, "Date and Time Options".

DATE Values

DATE values have independent input and output formats. You can enter date values in one style and report them in a different style. To change the order of the month, day, and year components, see the DATEORDER option. When you show a date value in output, the format depends on the DATEFORMAT option. The default format is a 2-digit day, a 3-letter month, and a 2-digit year; for example, 03MAR97. The text for the month names depends on the MONTHNAMES option.

To determine whether a text expression (such as an expression with a data type of TEXT or ID) represents a valid DATE value, use the ISDATE program.

DATETIME Values

The format and language of DATETIME values are controlled by the settings of the NLS_DATE_FORMAT and NLS_DATE_LANGUAGE options described in "NLS Options". The DATETIME data type is supported by Oracle Database standard libraries and operates the same way in the OLAP DML as it does in SQL. The DATEORDER, DATEFORMAT, and MONTHNAMES options, which control the formatting of DATE values, have no effect on DATETIME values. However, DATETIME and DATE values can be used interchangeably in most DML statements.

Valid DATE Values

A valid DATE value must fall between January 1, 1000, and December 31, 9999. It must conform to one of three styles: numeric, packed numeric, or month name. You can mix these styles throughout a session.

Numeric style

Specify the day, month, and year as three INTEGER values with one or more separators between them, using these rules:

The day and month components can have one digit or two digits.
For any year, the year component can have four digits (for example, 1997). For years in the range 1950 to 2049, the year component can, alternatively, have two digits (50 represents 1950, and so on).
To separate the components, you can use a space, dash (-), slash (/), colon (:), or comma (,).

Examples: '24/4/97' or '24-04-1997'

Packed numeric style

Specify the day, month, and year as three INTEGER values with no separators between them, using these rules:

The day and month components must have two digits. When the day or month is less than 10, it must be preceded by a zero.
For any year, the year component can have four digits (for example, 1997). For years in the range 1950 to 2049, the year component can, alternatively, have two digits (50 represents 1950, and so on).
You cannot use any separators between the date components.

Examples: '240497' or '04241997'

Month name style

Specify the day and year as INTEGER values and the month as text, using these rules:

The month component must match one of the names listed in the MONTHNAMES option. You can abbreviate the month name to one letter or more, when you supply enough letters to uniquely match the beginning of a name in MONTHNAMES. The case of the letters in the month component (uppercase or lowercase) does not need to match the case in MONTHNAMES.
The day component can have one digit or two digits.
For any year, the year component can have four digits (for example, 1997). For years in the range 1950 to 2049, the year component can, alternatively, have two digits (50 represents 1950, and so on).
When the day and year components are adjacent, they must have at least one separator between them. As separators, you can use a space, dash (-), slash (/), colon (:), or comma (,). When you want, you can place one or more separators between the day and month or between the year and month.

Examples: '24APR97' or '24 ap 97' or 'April 24, 1997'

Calculating Dates

You can add numbers to a DATE or DATETIME value, or subtract numbers from them. Whole numbers are calculated as days, and decimal values are calculated as fractions of a day. For example, SYSDATE+1.5 adds 1 day and 12 hours to the current date and time. You cannot divide or multiply DATE or DATETIME values, and you cannot subtract them from numbers. For example, 1-SYSDATE and 1*SYSDATE return errors.