Oracle DB: How to Pick the Right Function for Current Date and Time

When working with date and time in Oracle, you have several functions available to get the current date and time. Three important ones are CURRENT_DATE, CURRENT_TIMESTAMP, and SYSDATE. Let’s see how they are different and when you should use each one.

The CURRENT_DATE function gives you the current date and time based on the time zone of the session you are in. It returns this information in a simple DATE format, which includes the date and time up to the second but does not show fractions of a second or the time zone. For example, if you run:

SELECT CURRENT_DATE FROM dual;

You might get a result like 29-JUL-24 03:43:19 PM. This shows the current date and time according to your session’s time zone.

You can set the session’s time zone to a specific offset from UTC. For example, to set the time zone to UTC+5:30:

ALTER SESSION SET TIME_ZONE = '+05:30';

Use CURRENT_DATE when you need the date and time for tasks that are specific to a certain time zone. It’s good for simple reports or calculations that don’t need to worry about fractions of a second or different time zones.

The CURRENT_TIMESTAMP function provides more detail. It gives you the current date and time, including fractions of a second and the time zone. This function returns the value in the TIMESTAMP WITH TIME ZONE format. For example, if you run:

SELECT CURRENT_TIMESTAMP FROM dual;

You might see something like 29-JUL-24 15.43.19.123456 PM +01:00. This includes the date, time, fractions of a second, and the time zone offset.

Use CURRENT_TIMESTAMP when you need precise time details, such as for logging events, tracking changes, or working across different time zones. It’s useful when you need to know the exact time down to the fraction of a second and the time zone.

The SYSDATE function gives you the current date and time from the database server’s clock. It’s similar to CURRENT_DATE in that it returns the date and time up to the second but not fractions of a second or time zone information. For example, if you run:

SELECT SYSDATE FROM dual;

You might get 29-JUL-24 03:43:19 PM. This shows the current date and time based on the server’s clock.

Use SYSDATE when you need the current date and time according to the server, not the session. This is helpful for server-side operations, scheduling tasks, and ensuring consistency across database operations that rely on the server’s time.

With this information, you should now be able to choose the right function for your use case.