HAVING COUNT(field) fails when COUNT(field) has no alias

[fupelaqu]

Description

When a GROUP BY query uses COUNT(field) (not COUNT(*)) without an alias and references it in a HAVING clause, the bucket_selector's buckets_path maps the metric name to itself instead of the actual Elasticsearch aggregation name.

Root Cause

In extractMetricsPathForBucket (bridge/…/ElasticAggregation.scala), when the lookup matches via agg.field == metricName, the return value metricName -> metricName is incorrect because:

• metricName = "field_name" (from Identifier.metricName)
• aggName (local) = "count_field_name" (from s"${aggType}_${sourceField}")
• The bucket_selector gets {"field_name": "field_name"} but the actual ES aggregation is named "count_field_name"

The correct return should map metricName to the local aggregation name (last segment of ElasticAggregation.aggName).

Complexity

The fix is non-trivial because ElasticAggregation.aggName in the case class stores the full nested path (e.g., "inner_products.filtered_agg.min_price"), not just the local name. Extracting the local name requires splitting on . which may be fragile. A cleaner approach would be to store the local aggregation name as a separate field in the case class.

Workaround

Always provide an alias for aggregations used in HAVING:

HAVING COUNT(field) > 5        -- broken
HAVING cnt > 5                 -- works (with COUNT(field) AS cnt in SELECT)

Related

• Issue HAVING COUNT(*) fails when COUNT(*) has no alias #50 — HAVING COUNT(*) without alias (fixed via consistent aggName computation)