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

# DROP PROCEDURE statement

The DROP PROCEDURE statement deletes a user-defined procedure (UDP) in the used schema.

Note

An operation involving a non-default schema or an object in it requires access to the schema, either implicitly or through an explicit `USAGE` grant, as well as the privilege required for the operation. The schema access check and the privilege check for the requested operation are independent; satisfying one does not satisfy the other. Schema access control does not apply to temporary graphs or built-in procedures and functions. For more information, see [Schema access control](https://dev-docs.nebula-graph.io/v5.3.2/server-admin/authorization/schema-access-control/).

## Prerequisites

- The UDP is created. For more information, see [CREATE PROCEDURE](https://dev-docs.nebula-graph.io/v5.3.2/database-gql-reference/procedures/create/).

- To delete a UDP, you must either be the owner of the UDP, be granted to perform the action `DROP` on the UDP, or be granted to perform the action `DROP ANY PROCEDURE` on the used schema. For more information, see [Roles and privileges](https://dev-docs.nebula-graph.io/v5.3.2/server-admin/authorization/).

## Syntax

diagramsource

 drop_procedure_statement parameter_declaration  

````
drop_procedure_statement ::=
    'DROP' 'PROCEDURE' ('IF EXISTS')? procedure_name ( '(' ( parameter_declaration ( ',' parameter_declaration )* )? ')' )?

parameter_declaration  ::=
    parameter_name? parameter_type ('DEFAULT' default_value )?       

````

## Parameters

### `IF EXISTS`

This clause checks if the UDP to be deleted exists. If it does not exist, the UDP is not deleted and no exception is thrown.

If you do not specify this clause, an exception is thrown if the UDP to be deleted does not exist.

### `procedure_name`

The name of the UDP to be deleted.

To delete a UDP by name, ensure no other UDP with the same name exists in the used schema. Otherwise, you must specify both the name and parameter type to uniquely identify the UDP to be deleted.

### `parameter_name`

The name of the input parameter accepted by the UDP.

### `parameter_type`

The data type of the input parameter accepted by the UDP.

### `default_value`

The default value of the input parameter.

## Examples

### Drop a UDP by name

````
'''
// Create UDP `test1`
CREATE OR REPLACE PROCEDURE test1() RETURNS ret INT AS { RETURN 1 }
'''

'''
DROP PROCEDURE test1
'''

````

### Drop a UDP by name and parameter type

````
'''
// Create UDP `test2`
CREATE OR REPLACE PROCEDURE test2(a INT, b STRING) RETURNS ret INT AS { RETURN a }
'''

'''
DROP PROCEDURE test2(INT, STRING)
'''

````