Null value conditions

A null condition is used to detect NULL values.

Syntax

expr IS [ NOT ] NULL

Usage instructions

• IS NULL checks whether an expression is NULL. If the expression is NULL, it returns TRUE; otherwise, it returns FALSE.
• IS NOT NULL checks whether an expression is not NULL. If the expression is not NULL, it returns TRUE; otherwise, it returns FALSE.

Examples

obclient> CREATE TABLE emp (
  empno INT,
  last_name VARCHAR(20),
  comm_pct DECIMAL(5, 2)
);
obclient> INSERT INTO emp VALUES
  (1, 'Smith', NULL),
  (2, 'Jones', 0.10);

obclient> SELECT last_name FROM emp WHERE comm_pct IS NULL ORDER BY last_name;