Logical Operators v13
The usual logical operators are available: AND, OR, NOT
SQL uses a three-valued Boolean logic where the null value represents "unknown". Observe the following truth tables:
AND/OR Truth Table
| 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 |
NOT Truth Table
| 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.