ASA SQL Reference
SQL Language Elements
Search conditions
Three-valued logic
The following tables display how the AND, OR, NOT, and IS logical operators of SQL work in three-valued logic.
AND operator
|
AND
|
TRUE
|
FALSE
|
UNKNOWN
|
|---|
|
TRUE
|
TRUE
|
FALSE
|
UNKNOWN
|
|
FALSE
|
FALSE
|
FALSE
|
FALSE
|
|
UNKNOWN
|
UNKNOWN
|
FALSE
|
UNKNOWN
|
OR operator
|
OR
|
TRUE
|
FALSE
|
UNKNOWN
|
|---|
|
TRUE
|
TRUE
|
TRUE
|
TRUE
|
|
FALSE
|
TRUE
|
FALSE
|
UNKNOWN
|
|
UNKNOWN
|
TRUE
|
UNKNOWN
|
UNKNOWN
|
NOT operator
|
TRUE
|
FALSE
|
UNKNOWN
|
|---|
|
FALSE
|
TRUE
|
UNKNOWN
|
IS operator
|
IS
|
TRUE
|
FALSE
|
UNKNOWN
|
|---|
|
TRUE
|
TRUE
|
FALSE
|
FALSE
|
|
FALSE
|
FALSE
|
TRUE
|
FALSE
|
|
UNKNOWN
|
FALSE
|
FALSE
|
TRUE
|