Logical Operators¶
For logical operators, boolean expressions or expressions that evaluates to an INTEGER value are specified as operands; TRUE, FALSE or NULL is returned as a result. If the INTEGER value is used, 0 is evaluated to FALSE and the other values are evaluated to TRUE. If a boolean value is used, 1 is evaluated to TRUE and 0 is evaluated to FALSE.
The following table shows the logical operators.
Logical Operators
| Logical Operator | Description | Condition |
|---|---|---|
| AND , && | If all operands are TRUE , it returns TRUE . | a AND b |
| OR, || | If none of operands is NULL and one or more operands are TRUE , it returns TRUE . If pipes_as_concat is no that is a parameter related to SQL statements, a double pipe symbol can be used as OR operator. | a OR b |
| XOR | If none of operand is NULL and each of operand has a different value, it returns TRUE . | a XOR b |
| NOT , ! | A unary operator. If a operand is FALSE , it returns TRUE . If it is TRUE , returns FALSE . | NOT a |
Truth Table of Logical Operators
| a | b | a AND b | a OR b | NOT a | a XOR b |
|---|---|---|---|---|---|
| TRUE | TRUE | TRUE | TRUE | FALSE | FALSE |
| TRUE | FALSE | FALSE | TRUE | FALSE | TRUE |
| TRUE | NULL | NULL | TRUE | FALSE | NULL |
| FALSE | TRUE | FALSE | TRUE | TRUE | TRUE |
| FALSE | FALSE | FALSE | FALSE | TRUE | FALSE |
| FALSE | NULL | FALSE | NULL | TRUE | NULL |