oracle database sysdate

SYSDATE is a function in Oracle that returns the current system date and time, which can be used to store creation dates, comparison dates, and set deadlines. How to use: SELECT SYSDATE FROM dual;. The output can be formatted using the TO_CHAR function. Note that SYSDATE is affected by the server time zone and is avoided in the WHERE clause for performance improvement.

The meaning of SYSDATE in Oracle database

SYSDATE is a special function in Oracle database that returns the current system date and time. It is a very useful function that can be used for a variety of purposes, such as:

• Store creation or update dates in tables
• Comparison of dates and times
• Set an expiration date or deadline

How to use SYSDATE

Using the SYSDATE function is very simple, just enter it in the SQL statement:

 <code>SELECT SYSDATE FROM dual;</code>

This returns the date and time of the current system. You can also use the SYSDATE function to compare dates and times. For example, the following statement will return all records updated by January 1, 2023:

 <code>SELECT * FROM table_name WHERE update_date </code>

Format SYSDATE output

By default, the SYSDATE function returns a string containing the date and time. You can use the TO_CHAR function to format the SYSDATE output to a specific format. For example, the following statement formats the SYSDATE output to "YYYY-MM-DD HH24:MI:SS" format:

 <code>SELECT TO_CHAR(SYSDATE, 'YYYY-MM-DD HH24:MI:SS') FROM dual;</code>

Notice:

• SYSDATE is an Oracle-specific function and may not be applicable in other database management systems.
• The value of SYSDATE is based on the server's time zone, so if you access the database across time zones, the date and time you return may be different from your local time zone.
• You should avoid using the SYSDATE function in the WHERE clause, as this may cause performance issues.

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