Oracle SYS_CONTEXT() Function

Oracle SYS_CONTEXT() is a built-in function that returns the value of the given parameter associated with the given context at the current time.

Oracle `SYS_CONTEXT()` Syntax

Here’s the syntax for the Oracle SYS_CONTEXT() function:

SYS_CONTEXT('namespace', 'parameter' [, length ])

'namespace': Required. The namespace. Oracle provides two built-in namespaces: USERENV (current session) and SYS_SESSION_ROLES (indicates whether specified roles are enabled for the session).
'parameter': Required. The parameter name.
length: Optional. The maximum return value is 256 bytes, which you can override with this parameter.

The Oracle SYS_CONTEXT() function returns the value of the given parameter associated with the given context at the current time.

If any of the parameters are NULL, SYS_CONTEXT() returns NULL.

Here are some examples that demonstrate how to use the Oracle SYS_CONTEXT() function.

The following statement returns the name of the user who logged in to the database:

SELECT
    SYS_CONTEXT('USERENV', 'SESSION_USER')
FROM dual;

Output:

SYS_CONTEXT('USERENV','SESSION_USER')
________________________________________
SYSTEM

If any of the parameters are NULL, SYS_CONTEXT() returns NULL.

SET NULL 'NULL';
SELECT
    SYS_CONTEXT(NULL, NULL) NULL_1,
    SYS_CONTEXT(NULL, NULL, NULL) NULL_2
FROM dual;

Output:

NULL_1    NULL_2
_________ _________
NULL      NULL

In this example, we use the SET NULL 'NULL'; statement to display NULL values as the string 'NULL'.

Oracle SYS_CONTEXT() is a built-in function that returns the value of the given parameter associated with the given context at the current time.

You can find more information about this function here.