Source: https://dev-docs.nebula-graph.io/v5.3.2/database-gql-reference/fe/expressions/logical/
Documentation version: v5.3.2

# Logical value expression

The logical value expression performs logical operations and returns a result of the boolean type.

## Syntax

diagramsource

 logical_value_expression  

````
logical_value_expression ::=
    value_expression ( 'AND' | 'OR' ) value_expression

````

## Parameters

### `value_expression`

The value expression on which the logical operation is performed. For more information, see [Expressions](https://dev-docs.nebula-graph.io/v5.3.2/database-gql-reference/fe/).

### `AND | OR`

The type of logical operation, including `AND` and `OR`.

The following sections list the truth tables for `AND` and `OR` respectively.

#### Truth table for the AND Boolean operator

 | AND | True | False | Unknown
 | True | true | false | null
 | False | false | false | false
 | Unknown | null | false | null

#### Truth table for the OR Boolean operator

 | OR | True | False | Unknown
 | True | true | true | true
 | False | true | false | null
 | Unknown | true | null | null

## Examples

### Use the OR operator

````
RETURN true OR false AS a

````

Return:

````
+------+
| a    |
+------+
| true |
+------+

````

### Use the AND operator

````
RETURN 1=2 AND 1=1 AS b

````

Return:

````
+-------+
| b     |
+-------+
| false |
+-------+

````