How to Calculate Date Differences in Oracle Without the DATEDIFF Function?

DATEDIFF Function in Oracle

The DATEDIFF function is commonly used in other database systems such as SQL Server and MySQL to calculate the difference between two dates. However, this function is not natively available in Oracle.

Method to Calculate Date Difference in Oracle

To determine the difference between dates in Oracle, you can utilize the following methods:

• Simple Date Subtraction: Directly subtract two dates to obtain the difference in days.

SELECT TO_DATE('2000-01-02', 'YYYY-MM-DD') -  
       TO_DATE('2000-01-01', 'YYYY-MM-DD') AS DateDiff
FROM   dual

Note that unlike other database systems, Oracle requires a FROM clause in select statements. In the provided example, the dual table is used as a placeholder for this clause.

Additional Functions for Date Manipulation

Oracle offers additional functions for manipulating dates:

• INTERVAL: Used for defining a specific time period.
• TRUNC: Truncates a date value to a specified unit (e.g., year, month, day).

These functions can be employed to achieve more complex date calculations, such as calculating elapsed time with different units of measurement.

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