Source: https://dev-docs.nebula-graph.io/v5.3.2/database-gql-reference/dql/let/
Documentation version: v5.3.2

# LET statement

The LET statement declares variables that can be used in subsequent statements.

The `LET` statement defines variables by adding new columns to the output table of the current statement. Variables declared in the `LET` statement must be included in a `RETURN` statement to be usable in statements following the keyword `NEXT` that follows the `RETURN` statement. For more information, see [Statement block](https://dev-docs.nebula-graph.io/v5.3.2/database-gql-reference/statement-block/).

## Syntax

diagramsource

 let_statement  

````
let_statement ::=
    'LET' variable_name '=' value_expression (',' variable_name '=' value_expression)*

````

## Parameters

### `variable_name`

The name of the variable declared. The name can be a regular identifier or a delimited identifier enclosed with backticks (```). It must be unique. For more information about identifiers, see [Rules for naming identifiers](https://dev-docs.nebula-graph.io/v5.3.2/database-gql-reference/overview/keywords-identifiers/).

### `value_expression`

A constant or value expression, the evaluated value of which is assigned to the variable declared. The value can be of any value type. For more information, see [Value expressions](https://dev-docs.nebula-graph.io/v5.3.2/database-gql-reference/fe/).

## Examples

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

### Assign constant values to variables

````
'''
LET a = 1, b = 2, c = 3 
RETURN a, b, c
'''

````

Return:

````
+---+---+---+
| a | b | c |
+---+---+---+
| 1 | 2 | 3 |
+---+---+---+

````

### Define variables with expressions

````
'''
LET a = 1 + 2, b = 3 + 4 
LET c = a + b 
RETURN a, b, c
'''

````

Return:

````
+---+---+----+
| a | b | c  |
+---+---+----+
| 3 | 7 | 10 |
+---+---+----+

````

### Define variables with node properties

````
'''
USE movie 
MATCH (v@Actor) WHERE v.id = 199 
LET a = v.name, b = upper(a) 
RETURN b
'''

````

Return:

````
+--------------+
| b            |
+--------------+
| JULIE KAVNER |
+--------------+

````

### Define a variable with a subquery

````
'''
LET a = VALUE { USE movie MATCH (v@Actor) WHERE v.id = 199 RETURN v.name LIMIT 1 } 
RETURN a
'''

````

Return:

````
+--------------+
| a            |
+--------------+
| Julie Kavner |
+--------------+

````

### Use variables in subsequent statements

````
'''
USE movie 
LET a = 199 
RETURN a 
NEXT 
USE movie 
MATCH (v WHERE v.id = a) RETURN v
'''

````

Return:

````
+--------------------------------------------------------------------------------------------+
| v                                                                                          |
+--------------------------------------------------------------------------------------------+
| (289113618996264961@Movie:Movie{id:199,name:"Star Trek: First Contact"})                   |
| (288832144019554307@User:Person{id:199})                                                   |
| (288269194066132994@Actor_renamed:Person{birthDate:1951-09-07,id:199,name:"Julie Kavner"}) |
+--------------------------------------------------------------------------------------------+

````