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PROFESSIONAL-DATA-ENGINEER · Question #54
Suppose you have a table that includes a nested column called "city" inside a column called "person", but when you try to submit the following query in BigQuery, it gives you an error. SELECT person F
The correct answer is A. Add ", UNNEST(person)" before the WHERE clause.. Explanation/Reference: To access the person.city column, you need to "UNNEST(person)" and JOIN it to table1 using a comma. https://cloud.google.com/bigquery/docs/reference/standard-sql/migrating-from-legacy-sql#nested_repeated_results
Submitted by parkjh· Mar 30, 2026Building and operationalizing data processing systems
Question
Suppose you have a table that includes a nested column called "city" inside a column called "person", but when you try to submit the following query in BigQuery, it gives you an error. SELECT person FROM
project1.example.table1 WHERE city = "London" How would you correct the error?Options
- AAdd ", UNNEST(person)" before the WHERE clause.
- BChange "person" to "person.city".
- CChange "person" to "city.person".
- DAdd ", UNNEST(city)" before the WHERE clause.
How the community answered
(36 responses)- A94% (34)
- C3% (1)
- D3% (1)
Explanation
Explanation/Reference: To access the person.city column, you need to "UNNEST(person)" and JOIN it to table1 using a comma. https://cloud.google.com/bigquery/docs/reference/standard-sql/migrating-from-legacy-sql#nested_repeated_results
Topics
#BigQuery nested fields#UNNEST#SQL syntax#repeated records
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