Logical Functions

**Table 1** Logical functions
SQL Function	Return Type	Description
boolean1 OR boolean2	BOOLEAN	Returns TRUE if boolean1 or boolean2 is TRUE. Supports three-valued logic. For example, true \|\| Null(BOOLEAN) returns TRUE.
boolean1 AND boolean2	BOOLEAN	Returns TRUE if both boolean1 and boolean2 are TRUE. Supports three-valued logic. For example, true && Null(BOOLEAN) returns UNKNOWN.
NOT boolean	BOOLEAN	Returns TRUE if the boolean value is FALSE; returns FALSE if the boolean value is TRUE; returns UNKNOWN if the boolean value is UNKNOWN.
boolean IS FALSE	BOOLEAN	Returns TRUE if the boolean value is FALSE; returns FALSE if boolean is TRUE or UNKNOWN.
boolean IS NOT FALSE	BOOLEAN	Returns TRUE if boolean is TRUE or UNKNOWN; returns FALSE if boolean is FALSE.
boolean IS TRUE	BOOLEAN	Returns TRUE if boolean is TRUE; returns FALSE if boolean is FALSE or UNKNOWN.
boolean IS NOT TRUE	BOOLEAN	Returns TRUE if boolean is FALSE or UNKNOWN; returns FALSE if boolean is TRUE.
boolean IS UNKNOWN	BOOLEAN	Returns TRUE if the boolean value is UNKNOWN; returns FALSE if boolean is TRUE or FALSE.
boolean IS NOT UNKNOWN	BOOLEAN	Returns TRUE if boolean is TRUE or FALSE; returns FALSE if the boolean value is UNKNOWN.