42803ERRORTier 2 — Caution✅ HIGH confidence

grouping error

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

What this means

SQLSTATE 42803 is raised when a column referenced in the SELECT list or HAVING clause is neither an aggregate function nor part of the GROUP BY clause. This violates SQL grouping rules.

Why it happens

1A non-aggregated column in the SELECT list is not listed in the GROUP BY clause
2A HAVING clause references a column that is not in GROUP BY and not wrapped in an aggregate

How to reproduce

SELECT with a non-aggregated column missing from GROUP BY.

trigger — this will ERROR

SELECT department, name, COUNT(*)
FROM employees
GROUP BY department;
-- name is not in GROUP BY or an aggregate

ERROR: column "employees.name" must appear in the GROUP BY clause or be used in an aggregate function

Fix 1: Add the column to GROUP BY

When the column should be part of the grouping key.

fix

SELECT department, name, COUNT(*)
FROM employees
GROUP BY department, name;

Why this works

Adding name to GROUP BY makes it part of the group identifier, satisfying the SQL grouping rule.

Fix 2: Wrap the column in an aggregate function

When you want one representative value from the group.

fix

SELECT department, MAX(name), COUNT(*)
FROM employees
GROUP BY department;

Why this works

Aggregate functions (MAX, MIN, STRING_AGG, etc.) reduce multiple values to one, which is valid in a grouped SELECT.

Sources

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

🔧 Source ref: Class 42 — Syntax Error or Access Rule Violation

Confidence assessment

✅ HIGH confidence

Standard SQLSTATE for GROUP BY violations. Stable across all Postgres versions.