Absolute Database supports usual logical operators:
Operator
|
Description
|
Example
|
AND
|
Both conditions must apply
|
(ID > 1) AND (ID < 100)
|
OR
|
Either condition can apply
|
(Color = 'Blue') OR (Color = 'Red')
|
NOT
|
Logical opposite of condition
|
NOT (State = 'CA')
|
SQL uses a three-valued Boolean logic where the null value represents "unknown".
Observe the following truth tables:
a
|
b
|
a AND b
|
a OR b
|
TRUE
|
TRUE
|
TRUE
|
TRUE
|
TRUE
|
FALSE
|
FALSE
|
TRUE
|
TRUE
|
NULL
|
NULL
|
TRUE
|
FALSE
|
FALSE
|
FALSE
|
FALSE
|
FALSE
|
NULL
|
FALSE
|
NULL
|
NULL
|
NULL
|
NULL
|
NULL
|
a
|
NOT a
|
TRUE
|
FALSE
|
FALSE
|
TRUE
|
NULL
|
NULL
|
The operators AND and OR are commutative, that is, you can switch the left and right operand without affecting the result.
|
|
