SQLSTATE P0003Severity lowLab verified

Incident brief

Too many rows

A PL/pgSQL SELECT ... INTO STRICT matched more than one row. PostgreSQL raised an error instead of silently picking one of them.

What lands in your log

ERROR: query returned more than one row

Reproduced on PostgreSQL 16.14Verified 2026-07-16 (Docker lab, PostgreSQL 16.14)Verified against PostgreSQL 16.14 in an isolated lab environment

In 10 seconds

What triggers it: Run SELECT ... INTO STRICT against a query that matches two or more rows.
Fix: Add ORDER BY plus LIMIT 1 to the STRICT select if exactly one specific row is genuinely the right answer.
Proof: Reproduced on PostgreSQL 16.14 → A SELECT ... INTO STRICT that matched two rows was rejected with SQLSTATE P0003. The session was unaffected afterward.

Fix

What to do right now

Application-level steps for this error.

Add ORDER BY plus LIMIT 1 to the STRICT select if exactly one specific row is genuinely the right answer.
Or restructure the query to aggregate or otherwise guarantee a single row, if that's the actual intent.

Fix SQL

DO $$
DECLARE
  x int;
BEGIN
  SELECT n INTO STRICT x FROM (VALUES (1),(2)) t(n) ORDER BY n LIMIT 1;
  RAISE NOTICE 'x = %', x;
END $$;

For this error

See this error live on the server

Run these against the affected instance to confirm the diagnosis before you act.

Too many rows is raised by SELECT ... INTO STRICT. Count the rows for the exact predicate without STRICT before deciding whether the data or the query contract is wrong.

Cardinality of the STRICT predicate

Replace the read-only query from the function; the predicate is invalid for STRICT when this test is true.

SELECT count(*) AS rows_returned,
       count(*) > 1 AS would_raise_p0003
FROM (<strict_select_without_into>) AS candidate;

Reproduce & verify

A real, single-session PostgreSQL reproduction

A literal transcript of SQL run against a live PostgreSQL instance in an isolated lab. The commands below are exactly what was executed.

1Run SELECT ... INTO STRICT against a query that matches two or more rows.
2SQLSTATE P0003 is reported; the block aborts.

One client: a DO block runs SELECT ... INTO STRICT against an inline VALUES list matching two rows.

Schema setup

-- No table needed: the failure is self-contained via an inline VALUES list.
SELECT 'no schema required' AS setup_note;

The STRICT select with two matching rows

DO $$
DECLARE
  x int;
BEGIN
  SELECT n INTO STRICT x FROM (VALUES (1),(2)) t(n);
END $$;

Confirming the session still works

SELECT 1 AS session_still_alive;

What PostgreSQL actually returned

Schema setup output

     setup_note     
--------------------
 no schema required
(1 row)

The STRICT select with two matching rows output

ERROR:  query returned more than one row
HINT:  Make sure the query returns a single row, or use LIMIT 1.
CONTEXT:  PL/pgSQL function inline_code_block line 5 at SQL statement

Confirming the session still works output

 session_still_alive 
---------------------
                   1
(1 row)

Connected

Everything this error touches

Every page this SQLSTATE connects to: the concept that explains it, the runbooks that fix it, the parameters you tune to prevent it, and the sibling errors it travels with. All real cross-references. Jump straight in, or open the full interactive map.

Open in the interactive map →

Related errors
Raise exception No data found

Verification

PG 16.14

Last verified: 2026-07-16 (Docker lab, PostgreSQL 16.14)
Verification scope: Verified against PostgreSQL 16.14 in an isolated lab environment
Audit status: reviewed

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