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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)
  • A
    94% (34)
  • C
    3% (1)
  • D
    3% (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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