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Logical Operators
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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.

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