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Description

This error indicates that PostgreSQL cannot find a function or operator that matches the name and argument types specified in your query. It's a syntax error or a violation of access rules, meaning the database system doesn't recognize the requested operation.

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Error Message

undefined function

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Known Causes

4 known causes

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Function Name Typo or Misspelling

The function or operator name used in the SQL query contains a typo or does not exactly match any existing function or operator in the database.

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Mismatched Argument Types

While a function with the specified name might exist, no overload matches the exact number or data types of the arguments provided in the query.

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Missing Extension or Search Path Issue

The required function belongs to a PostgreSQL extension that is not installed or enabled, or the function's schema is not included in the current `search_path`.

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Incorrect Database or Schema Context

The query is being executed in a database or schema where the intended function or operator has not been created or is not accessible.

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Solutions

4 solutions available

1. Verify Function/Operator Name and Schema easy

Ensure the function or operator name is spelled correctly and is accessible within the current schema search path.

1

Double-check the spelling of the function or operator name in your SQL query against its definition in PostgreSQL.

SELECT my_custom_function(arg1, arg2);

2

If the function or operator is not in the default `public` schema, qualify it with its schema name. For example, if your function is in a schema named `my_schema`, use `my_schema.my_custom_function`.

SELECT my_schema.my_custom_function(arg1, arg2);

3

Check your `search_path` configuration. If the function/operator resides in a schema not currently in your `search_path`, you'll need to add it or qualify the call.

SHOW search_path;

4

To temporarily add a schema to the search path for the current session:

SET search_path TO my_schema, public;

2. Confirm Data Types Match Function/Operator Signature medium

The error can occur if the data types of the arguments provided to the function or operator do not match any of its defined signatures.

1

Identify the function or operator causing the error and examine its signature. You can do this by querying the `pg_proc` (for functions) or `pg_operator` (for operators) catalog tables.

SELECT proname, pg_get_function_identity_arguments(oid) FROM pg_proc WHERE proname = 'my_custom_function';

2

Compare the data types of the values you are passing in your query to the expected data types in the function/operator signature. Pay close attention to implicit type casting rules in PostgreSQL.

-- Example: If my_custom_function expects (integer, text)
SELECT my_custom_function(10, 'hello'); -- Correct
SELECT my_custom_function('10', 'hello'); -- Potentially incorrect if '10' is not implicitly cast to integer

3

Explicitly cast your arguments to the correct data types if necessary.

SELECT my_custom_function(CAST('10' AS integer), 'hello');

3. Install or Enable the Required Extension medium

The function or operator might belong to a PostgreSQL extension that is not currently installed or enabled in your database.

1

Determine which extension provides the function or operator. This might be indicated in your application's documentation or by searching online for the function/operator name.

SELECT * FROM pg_extension;

2

If the extension is not listed, you need to create it. Replace `extension_name` with the actual name of the extension.

CREATE EXTENSION extension_name;

3

After creating the extension, re-run your query. If the extension was already created but not enabled in the current schema's `search_path`, you might need to adjust the `search_path` as described in Solution 1.

SET search_path TO extension_schema, public;

4. Check for Typo in Function/Operator Name or Definition easy

A simple typo in the function or operator's definition could lead to this error.

1

If you are the author of the function or operator, carefully review its `CREATE FUNCTION` or `CREATE OPERATOR` statement for any spelling mistakes. This includes the function/operator name itself, as well as any names of other functions or operators used within its definition.

-- Example of a potential typo in function definition
CREATE FUNCTION my_functin(int) RETURNS int AS $$
  SELECT $1 + 1;
$$ LANGUAGE sql;
-- The correct spelling should be 'my_function'

2

If the function/operator is part of a third-party library or extension, verify you've installed and referenced it correctly. Consult the documentation for that library/extension.

No direct code snippet, requires external documentation review.

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Related Errors

5 related errors

PostgreSQL Error 42883: Undefined Function or Operator