SQL GROUP BY Error
A selected field is neither grouped nor aggregated.
LIKELY CAUSE
Why it happens
Define the intended reporting grain and aggregate the remaining fields.
SAFE FIX
What to do
Every detail column changes the grouping grain.
Debug in this order
- Reproduce the problem on the smallest sample that still fails.
- Inspect the exact keys, types, ranges or markup involved instead of only the displayed value.
- Fix the root cause, then rerun the original case and one known-good case.
- Document the rule if the same problem can return in recurring work.
Do not hide an unexplained data error with a cosmetic workaround. Make the input and matching logic predictable first.