INTERVAL Expressions

An interval expression yields a value of INTERVAL YEAR TO MONTH or INTERVAL DAY TO SECOND.

interval_expression::=

Text description of interval_expression

The interval_value_expression can be the value of an INTERVAL column or a compound expression that yields an interval value. Datetimes and intervals can be combined according to the rules defined in Table 2-2. The six combinations that yield interval values are valid in an interval expression.

For example, the following statement subtracts the value of the order_date column in the sample table orders (a datetime value) from the system timestamp (another datetime value) to yield an interval value expression:

SELECT (SYSTIMESTAMP - order_date) DAY TO SECOND from orders;