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

# Function value expression

The function value expression holds a function instance and returns the execution result of the function.

## Syntax

diagramsource

 function_value_expression  

````
function_value_expression ::=
    function_name '(' value_expression ( ',' value_expression )* ')'
  | function_name '()'

````

## Parameters

### `function_name`

The name of a function. For more information, see [Functions](https://dev-docs.nebula-graph.io/v5.3.2/database-gql-reference/fe/#functions).

### `value_expression`

An expression that returns a value used as the argument of a function. For more information, see [Value expressions](https://dev-docs.nebula-graph.io/v5.3.2/database-gql-reference/fe/#value_expressions).

## Examples

### Use the function `abs()`

The function `abs()` returns the absolute value of a number.

````
RETURN abs(-32.4) AS f1

````

Return:

````
+------+
| f1   |
+------+
| 32.4 |
+------+

````

### Use the function `substring()`

The function `substring()` returns a substring of a string.

````
RETURN substring("abc", 1, 1) AS f2

````

Return:

````
+----+
| f2 |
+----+
| a  |
+----+

````

### Use multiple function expressions

````
RETURN abs(-32.4) AS f1, substring("abc", 1, 1) AS f2

````

Return:

````
+------+----+
| f1   | f2 |
+------+----+
| 32.4 | a  |
+------+----+

````

### Use functions without arguments

````
RETURN date() AS currentDate

````

Return:

````
+-------------+
| currentDate |
+-------------+
| 2024-07-10  |
+-------------+

````