undefined_function Undefined Function — SQLSTATE 42883

No function or operator matches the name and argument types.

• The error is written to the server log and returned to the client carrying SQLSTATE 42883.
• Any driver (libpq, JDBC, psycopg, npgsql, pgx) surfaces this code in its error object so you can branch on it programmatically.
• PL/pgSQL can trap it by name: EXCEPTION WHEN undefined_function THEN.

Severity: ERROR  |  PostgreSQL versions: 12, 13, 14, 15, 16, 17

Reproduce with the exact statement and read the full message in the server log (raise log_min_messages / set log_min_error_statement for more context).

PostgreSQL resolves functions by name AND argument types; none matched the call.

Common causes:

• Wrong argument types (for example passing text where numeric is expected).
• A missing extension that provides the function.
• Wrong schema or search_path.
• Relying on an implicit cast that does not exist.

Steps to resolve 42883:

1. Check the signature: \df functionname in psql.
2. Cast arguments to the expected types.
3. Install/enable the providing extension: CREATE EXTENSION ...;.
4. Schema-qualify the function or fix search_path.

Reference: PostgreSQL error codes — Class 42 (Syntax Error or Access Rule Violation).