42P13ERRORTier 2 — Caution✅ HIGH confidence

invalid function definition

Category: Syntax Error or Access Rule ViolationVersions: All Postgres versions

What this means

SQLSTATE 42P13 is raised when a CREATE FUNCTION or CREATE PROCEDURE statement contains an invalid combination of options — for example, a STRICT function declared as returning SETOF type, or conflicting function attributes.

Why it happens

1Contradictory or mutually exclusive function attributes in CREATE FUNCTION
2Return type incompatible with declared function behaviour (e.g., STRICT + SETOF in some contexts)
3Invalid SQL function body for the declared return type

How to reproduce

CREATE FUNCTION with contradictory attributes.

trigger — this will ERROR

CREATE FUNCTION bad_fn() RETURNS VOID
LANGUAGE SQL STRICT
AS $ SELECT 1 $; -- VOID function with STRICT is invalid

ERROR: invalid use of STRICT with VOID return type

Fix 1: Remove conflicting function attributes

When CREATE FUNCTION raises 42P13.

fix

CREATE FUNCTION good_fn(x INT) RETURNS INT
LANGUAGE SQL STRICT
AS $ SELECT x * 2 $;

Why this works

Review function attributes for compatibility. STRICT is meaningful only for functions that receive input parameters and return a value.

Sources

📚 Official docs: https://www.postgresql.org/docs/current/errcodes-appendix.html

🔧 Source ref: Class 42 — Syntax Error or Access Rule Violation (Postgres-specific)

Confidence assessment

✅ HIGH confidence

Postgres-specific. Stable across versions.