Source: https://dev-docs.nebula-graph.io/v5.3.2/database-gql-reference/data-admin/show/show-functions/
Documentation version: v5.3.2

# SHOW FUNCTION / FUNCTIONS command

The SHOW FUNCTIONS command displays all the functions in the current schema. The `SHOW FUNCTION <function_name>` command displays the functions that match the specified function name.

If the current user does not have `USAGE` on the current schema, built-in functions are still returned, but user-defined functions in that schema are omitted. For more information, see [Schema access control](https://dev-docs.nebula-graph.io/v5.3.2/server-admin/authorization/schema-access-control/).

The following table describes the returned information:

 | Column | Description
 | `name` | The name of the function.
 | `signature` | The signature of the function. If the function is variadic, the last input parameter is followed by the ellipsis (`...`) symbol.
 | `comment` | The description of the function.

To view additional columns including the function `category` and `null_behavior`, use the `VERBOSE` option. See [Syntax](https://dev-docs.nebula-graph.io/v5.3.2/database-gql-reference/data-admin/show/show-functions/#syntax).

When the `VERBOSE` option is used, the following additional columns are returned:

 | Column | Description
 | `category` | The category of the function. Valid values are `SCALAR`, `AGGREGATE`, and `GQL UDF`. 

- `SCALAR` functions return a single value.
- `AGGREGATE` functions return a single value based on a set of input values.
- `GQL UDF` functions are user-defined functions written in GQL.

 | `null_behavior` | The NULL handling behavior of the function. Valid values are `DEFAULT` (returns NULL if any argument is NULL), `CUSTOM` (custom NULL handling), and `IGNORE` (ignores NULL values in aggregation).

## Syntax

diagramsource

 show_functions_command show_specific_function_statement optional_function_category  

````
show_functions_command ::=
    'SHOW' optional_function_category 'FUNCTIONS' 'VERBOSE'?

show_specific_function_statement ::=
    'SHOW' optional_function_category 'FUNCTION' function_name 'VERBOSE'?

optional_function_category ::=
    'SCALAR' | 'AGGREGATE' | 'ALL' | 'USER DEFINED' | 'GQL USER DEFINED'

````

- `optional_function_category`: Filters functions by category. If omitted, all functions are shown.
- `VERBOSE`: If specified, the output includes the additional `category` and `null_behavior` columns.

## Parameters

### `function_name`

The name of the function for which to display information.

You can specify a regular expression to match multiple functions. The regular expression must be enclosed in double quotes (`"`) or backticks (```). For example, `SHOW FUNCTION "collect.*"` matches all functions whose names start with `collect`.

To view all functions, use the `SHOW FUNCTIONS` command.

## Examples

### Show all functions

````
SHOW FUNCTIONS

````

Return:

````
+----------------------------------------------------+--------------------------------------------------------------------------+-------------------------------------------------------+
| name                                               | signature                                                                | comment                                               |
+----------------------------------------------------+--------------------------------------------------------------------------+-------------------------------------------------------+
| *                                                  | *(VECTOR, FLOAT) -> VECTOR                                               | Multiply vector by scalar                             |
...

````

### Show functions with VERBOSE option

````
SHOW FUNCTIONS VERBOSE

````

Return:

````
+----------------------------------------------------+--------------------------------------------------------------------------+-------------------------------------------------------+-----------+---------------+
| name                                               | signature                                                                | comment                                               | category  | null_behavior |
+----------------------------------------------------+--------------------------------------------------------------------------+-------------------------------------------------------+-----------+---------------+
| *                                                  | *(VECTOR, FLOAT) -> VECTOR                                               | Multiply vector by scalar                             | SCALAR    | DEFAULT       |
...

````

### Show functions with category

````
SHOW SCALAR FUNCTIONS VERBOSE

````

Return:

````
+----------------------------------------------------+--------------------------------------------------------------------------+-------------------------------------------------------+----------+---------------+
| name                                               | signature                                                                | comment                                               | category | null_behavior |
+----------------------------------------------------+--------------------------------------------------------------------------+-------------------------------------------------------+----------+---------------+
| *                                                  | *(VECTOR, FLOAT) -> VECTOR                                               | Multiply vector by scalar                             | SCALAR   | DEFAULT       |
|                                                    | *(VECTOR, INT64) -> VECTOR                                               |                                                       |          |               |
| +                                                  | +(VECTOR, FLOAT) -> VECTOR                                               | Add scalar to vector                                  | SCALAR   | DEFAULT       |
|                                                    | +(VECTOR, INT64) -> VECTOR                                               |                                                       |          |               |
|                                                    | +(VECTOR, VECTOR) -> VECTOR                                              | Add two vectors                                       | SCALAR   | DEFAULT       |
| -                                                  | -(VECTOR, FLOAT) -> VECTOR                                               | Subtract scalar from vector                           | SCALAR   | DEFAULT       |
|                                                    | -(VECTOR, INT64) -> VECTOR                                               |                                                       |          |               |
|                                                    | -(VECTOR, VECTOR) -> VECTOR                                              | Subtract two vectors                                  | SCALAR   | DEFAULT       |
| /                                                  | /(VECTOR, FLOAT) -> VECTOR                                               | Divide vector by scalar                               | SCALAR   | DEFAULT       |
|                                                    | /(VECTOR, INT64) -> VECTOR                                               |                                                       |          |               |
| abs                                                | abs(VECTOR) -> VECTOR                                                    | Absolute value of vector elements                     | SCALAR   | DEFAULT       |
...

````

### Show functions matching the specified function name

````
SHOW FUNCTION mod

````

Return:

````
+------+----------------------------------+---------+
| name | signature                        | comment |
+------+----------------------------------+---------+
| mod  | mod(DECIMAL, DECIMAL) -> DECIMAL | Modulus |
|      | mod(DOUBLE, DOUBLE) -> DOUBLE    |         |
|      | mod(FLOAT, FLOAT) -> FLOAT       |         |
|      | mod(INT16, INT16) -> INT16       |         |
|      | mod(INT32, INT32) -> INT32       |         |
|      | mod(INT64, INT64) -> INT64       |         |
|      | mod(INT8, INT8) -> INT8          |         |
|      | mod(UINT16, UINT16) -> UINT16    |         |
|      | mod(UINT32, UINT32) -> UINT32    |         |
|      | mod(UINT64, UINT64) -> UINT64    |         |
|      | mod(UINT8, UINT8) -> UINT8       |         |
+------+----------------------------------+---------+

````

### Show functions matching the specified regular expression

````
SHOW FUNCTION "collect.*"

````

Return:

````
+--------------+-------------------------------------+---------------------------+
| name         | signature                           | comment                   |
+--------------+-------------------------------------+---------------------------+
| collect      | collect(BOOL) -> LIST               | Collect values from group |
|              | collect(DATE) -> LIST               |                           |
|              | collect(DECIMAL) -> LIST            |                           |
|              | collect(DOUBLE) -> LIST             |                           |
|              | collect(DURATION) -> LIST           |                           |
|              | collect(EDGE) -> LIST               |                           |
...
|              | collect(ZONEDTIME) -> LIST          |                           |
| collect_list | collect_list(BOOL) -> LIST          | Collect values from group |
|              | collect_list(DATE) -> LIST          |                           |
|              | collect_list(DECIMAL) -> LIST       |                           |
...
+--------------+-------------------------------------+---------------------------+

````