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Applies to:
  • Plan -
  • Deployment -

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Summary

Issue: Queries fail with a Field not found error when a subquery’s table alias matches a column name used inside the subquery. Cause: The alias collides with the column of the same name, causing Braintrust SQL to fail resolving field references without indicating the naming conflict. Resolution: Rename the subquery alias to a value that does not match any column name referenced in the query.

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Resolution steps

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If you see Field not found with a subquery alias

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Step 1: Check for alias/column name collisions

Compare the alias assigned to your subquery against the column names inside it. A match between the alias and a column name causes the error. 
-- Fails: alias 'metrics' conflicts with column 'metrics'
SELECT metric AS name, AVG(value)
FROM (
  SELECT metric, value
  FROM experiment('724d08ca-d04e-4a40-8dd7-ad52498cdea3')
  UNPIVOT (value FOR metric IN (metrics))
) AS metrics
WHERE name IS NOT NULL
GROUP BY name

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Step 2: Rename the subquery alias

Change the alias to a value that does not match any column name in the subquery. 
-- Works: alias 'unpivoted' does not conflict with any column name
SELECT metric AS name, AVG(value)
FROM (
  SELECT metric, value
  FROM experiment('724d08ca-d04e-4a40-8dd7-ad52498cdea3')
  UNPIVOT (value FOR metric IN (metrics))
) AS unpivoted
WHERE name IS NOT NULL
GROUP BY name

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Otherwise, if the error persists after renaming

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Check all aliases in the query scope

Review every alias in the query — including column aliases and outer query references — to ensure none conflict with column names produced by any subquery.

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Contact support

If no naming conflict is found and the error continues, contact Braintrust support with your full query and the experiment ID for investigation.