3369
MySQLERRORNotableQuery ExecutionHIGH confidence
Non-aggregated column used with non-aggregate function in GROUP BY context
Production Risk
Medium — queries fail when ONLY_FULL_GROUP_BY is enforced.
How to reproduce
trigger — this will error
trigger — this will error
SELECT UPPER(name), COUNT(*) FROM t GROUP BY id;
expected output
ERROR 3369 (HY000): Non-aggregated column used in non-aggregate function.
Fix
Aggregate the column first
Aggregate the column first
SELECT UPPER(ANY_VALUE(name)), COUNT(*) FROM t GROUP BY id;
Why this works
ANY_VALUE reduces the group to a single value before passing it to UPPER().
What not to do
✕
Sources
Official documentation ↗
MySQL 8.0 — 3369 ER_NON_AGGREGATED_COLUMN_WITH_NONAGG_FUNCTION
Content generated with AI assistance and reviewed for accuracy. Found an error? hello@errcodes.dev