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

# Label expression

The label expression references one or more labels of a graph element.

Label expressions are often used in labeled predicates or graph patterns to filter graph elements based on their labels. For more information, see [Labeled predicate](https://dev-docs.nebula-graph.io/v5.3.2/database-gql-reference/fe/predicates/labeled/) and [Graph patterns](https://dev-docs.nebula-graph.io/v5.3.2/database-gql-reference/patterns/).

## Syntax

diagramsource

 label_expression label_factor  

````
label_expression ::=
    (label_factor ( '&' label_factor )* ) ( '|' (label_factor ( '&' label_factor )*) )*

label_factor ::=
    label_name
    | '%'
    | '(' label_expression ')'
    | '!' label_name
    | '!' '%'
    | '!' '(' label_expression ')'           

````

## Parameters

### `label_name`

The name of a label.

### `%`

The wildcard character that matches any label.

### `!`

The negation operator, which indicates the exclusion of a label.

### `&`

The conjunction operator, which indicates the intersection of two label factors.

### `|`

The disjunction operator, which indicates the union of two label factors.

## Examples

The following example is based on the [example dataset](https://dev-docs.nebula-graph.io/v5.3.2/database-gql-reference/overview/example-dataset/).

### Reference one label

````
'''
USE movie 
MATCH (v)-[e]->() 
WHERE v IS LABELED Person 
RETURN DISTINCT v.name AS name 
LIMIT 5
'''

````

The preceding statement selects nodes labeled `Person` and returns the names of the nodes.

Return:

````
+---------------+
| name          |
+---------------+
| null          |
| Jürgen Tonkel |
| Frank Harper  |
| James Doohan  |
| Fana Mokoena  |
+---------------+

````

### Reference a random label

````
'''
USE movie  
MATCH (v:%)-[e]->() 
RETURN DISTINCT v.name AS name 
LIMIT 5
'''

````

The preceding statement selects nodes with any label and returns the names of the nodes.

Return:

````
+------------------------+
| name                   |
+------------------------+
| Marco Kreuzpaintner    |
| Curt Siodmak           |
| David Lynch            |
| Billy Wilder           |
| Star Trek: Generations |
+------------------------+

````

### Exclude a label

````
'''
USE movie  
MATCH (v)-[e:!Act]->() 
RETURN DISTINCT e 
LIMIT 2
'''

````

The preceding statement selects edges that are not labeled `Act` and returns the information of the edges.

Return:

````
+----------------------------------------------------------------------+
| e                                                                    |
+----------------------------------------------------------------------+
| (289047300406247427)-[0@Watch:Watch{rate:4.0}]->(289108623949299713) |
| (289047300406247427)-[0@Watch:Watch{rate:1.0}]->(289138379482726401) |
+----------------------------------------------------------------------+

````

### Reference labels with the conjunction operator

````
'''
USE movie  
MATCH (v WHERE v IS LABELED Person&Movie)-[e]->() 
RETURN DISTINCT v.name AS name 
LIMIT 5
'''

````

The preceding statement selects nodes labeled `Person` and `Movie` and returns the names of the nodes.

Return:

````
+------+
| name |
+------+
+------+

````

### Reference labels with the disjunction operator

````
'''
USE movie  
MATCH (v)-[e]->() 
WHERE v IS LABELED Person|Movie 
RETURN DISTINCT v.name AS name 
LIMIT 5
'''

````

The preceding statement selects nodes labeled `Person` or `Movie` and returns the names of the nodes.

Return:

````
+-------------------------------------+
| name                                |
+-------------------------------------+
| Green Mile                          |
| Willy Wonka & the Chocolate Factory |
| Zatoichi                            |
| The Blue Angel                      |
| Sissi – The Young Empress           |
+-------------------------------------+

````