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GROUP BY on a SELECT alias groups by a non-existent field and returns zero rows with HTTP 200 #296
Description
Grouping by a column's SELECT alias produces an Elasticsearch terms aggregation on a field that does not exist. Validation passes, Elasticsearch answers HTTP 200 with zero buckets, and the caller sees an empty result for a query that should return every group.
Reproduction
SELECT country AS pays FROM bi_events GROUP BY pays -- 0 rows, HTTP 200
SELECT country AS pays FROM bi_events GROUP BY country -- correctMechanism
Select.fieldAliases is keyed identifierName -> alias, so an alias written in a GROUP BY never reverse-resolves. The bucket is built from the bare name, emitting terms { field: "pays" }. SingleSearch.validate() passes because the bucket's display name coincidentally equals the field's alias.
Measured bucket triples (name, path, sourceBucket):
| statement | bucket |
|---|---|
SELECT country AS pays FROM t GROUP BY country |
(pays, country, country) — correct |
SELECT country AS pays FROM t GROUP BY pays |
(pays, pays, pays) — wrong |
SELECT country AS pays, COUNT(*) AS cnt FROM t GROUP BY pays |
(pays, pays, pays) — the aggregate-bearing twin, wrong too |
SELECT UPPER(country) AS c FROM t GROUP BY c |
(c, c, c) — wrong for an expression alias |
Impact
Three statements in the captured BI corpus (Tableau and Superset) use this spelling. It is a silent wrong answer in the #205 / #207 / #209 / #224 / #253 family — the worst variety, since an empty success looks like "no matching data".
Resolution
A bare-name bucket resolves against the SELECT list's aliases at the AST level before the terms aggregation is built, so GROUP BY pays produces byte-identically the bucket GROUP BY country produces. A projected column always wins over an alias spelled the same. Expression aliases resolve to the aliased expression.
Fixing the resolution also required repairing two things it desynchronised: the terms order for ORDER BY <alias>, and the terms include/exclude for HAVING <alias> — both of which had been silently dropped.
Activity