ISNULL
Returns true if the value is NULL.
Syntax
ISNULL (val) (val IS NULL)
Arguments
val: any object
Return Type
Boolean
Examples
SELECT ISNULL(NULL), ISNULL(0), (NULL + 0 is NULL), (0 is NULL); **** +--------------+-----------+--------------------+-------------+ | ISNULL(NULL) | ISNULL(0) | (NULL + 0 is NULL) | (0 is NULL) | +--------------+-----------+--------------------+-------------+ | 1 | 0 | 1 | 0 | +--------------+-----------+--------------------+-------------+