SQLite nullif() function

Description

The nullif() function returns its first argument if the arguments are different and NULL if the arguments are the same.

Syntax:

nullif(X,Y);

Arguments:

SQLite Version: 3.8.5

Example: SQLite nullif() function

In the following SQLite statement since expressions are equal, it returns NULL.

SELECT nullif(2,2);

Here is the result.

Sample Output:

nullif(2,2)
------------------------------

Example: SQLite nullif() function with unequal arguments

In the following SQLite statement since expressions are not equal, it returns the first expression, i.e. 2.

SELECT nullif(2,3);

Here is the result.

Sample Output:

nullif(2,3)
------------------------------
2

Example: SQLite nullif() function using table

Sample table: departments

Sample table: employees

If you want to search, which department_id of the departments table does not exists into the employees table or does not matching with the department_id of the employees table, the following SQL can be used.

SELECT nullif((SELECT department_id FROM departments),(SELECT department_id FROM employees));

Here is the result.

Sample Output:

nullif((SELECT department_id FROM departments),(SELECT department_id FROM employees))
-------------------------------------------------------------------------------------
10

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