DROP FUNCTION

Enterprise command reference.

Command Snapshot

Field	Value
Category	DDL and Administration
Mutates Data	Yes/Depends
Scope	Cluster / Object
Privilege Model	Requires DDL/administrative privilege according to target object scope.

Purpose

Defines, changes, or removes schema and metadata objects.

Syntax

DROP FUNCTION [IF EXISTS] function_name ( [ [argument_name] argument_type [, ...] ] )

Operational Notes

• Use schema-qualified identifiers in automation and automation pipelines.
• Validate behavior in staging for cluster-impacting or governance-impacting changes.
• Confirm runtime effects through system tables and metrics before and after execution.

When to Use

• Use during planned schema and runtime administration changes.
• Use in automation pipelines with environment-specific validation and rollback strategy.

When Not to Use

• Avoid during incident windows unless the command is part of approved mitigation.
• Avoid schema changes in peak traffic windows without staged rollout.

Common Errors and Troubleshooting

Symptom	Likely Cause	Action
Permission denied / unauthorized	Missing privilege on object or cluster scope	Re-run with required grants or elevated admin role.
Analysis/parse error	Syntax variant or object shape mismatch	Compare with canonical syntax and object definition.
Runtime failure under load	Resource limits, breaker pressure, or node state transitions	Check sys.jobs, sys.operations, sys.checks, and retry after mitigation.

Cross-References

• SQL Command Catalog
• SQL Commands Index
• SQL Reference Overview

Detailed Reference

The DROP FUNCTION statement is used to remove a user-defined function (UDF) from a database. Below is a detailed explanation of its syntax, parameters, and usage in MonkDB.

SQL Statement

DROP FUNCTION [IF EXISTS] function_name ( [ [argument_name] argument_type [, ...] ] )

Description

The DROP FUNCTION command deletes a user-defined function from the database. It is particularly useful when you need to clean up unused or outdated functions. The function name and argument types must be specified to uniquely identify the function, especially in cases where functions are overloaded (multiple functions with the same name but different arguments).

Parameters

• IF EXISTS: This optional clause prevents errors if the specified function does not exist. When included, the command will execute successfully even if the function is missing, issuing a notice instead of an error.
• function_name: Specifies the name of the function to be dropped. This is mandatory and must match the name of the existing function.
• argument_name: Names given to arguments for documentation purposes during creation. These names are ignored during the DROP FUNCTION process; only argument types are considered.
• argument_type: Specifies the data type(s) of the arguments for the function. Necessary to uniquely identify overloaded functions.

Usage Notes

• Dropping a function removes both its executable code and metadata from the database.
• If multiple functions share the same name, specifying argument types ensures that only the intended version is removed.
• Functions dropped using this command cannot be recovered; they must be recreated if needed.

Examples

Example 1. Basic Example

DROP FUNCTION calculate_discount(INT, DECIMAL);

This removes the calculate_discount function with specific argument types.

Example 2. Using IF EXISTS

DROP FUNCTION IF EXISTS calculate_discount(INT, DECIMAL);

Here, no error will occur if calculate_discount does not exist.

Example 3. Dropping Multiple Functions

DROP FUNCTION IF EXISTS func_one(INT), func_two(VARCHAR);

This drops multiple functions in one statement.

Example 4. Overloaded Functions

If two functions share the same name but differ in argument types

DROP FUNCTION my_function(INT);
DROP FUNCTION my_function(VARCHAR);

Considerations

• Ensure you have appropriate privileges to drop a function (e.g., DBA or ownership rights).
• Dependent objects (like triggers or operators) may block deletion unless explicitly handled using cascading options (if supported by MonkDB).
• Always verify that dropping a function will not disrupt application workflows relying on it.

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See Also

• Create a function