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?
To access the person.city column, you need to "UNNEST(person)" and JOIN it to table1 using a comma.
What are two of the benefits of using denormalized data structures in BigQuery?
Denormalization increases query speed for tables with billions of rows because BigQuery's performance degrades when doing JOINs on large tables, but with a denormalized data structure, you don't have to use JOINs, since all of the data has been combined into one table. Denormalization also makes queries simpler because you do not have to use JOIN clauses.
Denormalization increases the amount of data processed and the amount of storage required because it creates redundant data.
Which of these statements about exporting data from BigQuery is false?
Data can be exported in CSV, JSON, or Avro format. If you are exporting nested or repeated data, then CSV format is not supported.
What are all of the BigQuery operations that Google charges for?
Google charges for storage, queries, and streaming inserts. Loading data from a file and exporting data are free operations.
Which of the following is not possible using primitive roles?
Primitive roles can be used to give owner, editor, or viewer access to a user or group, but they can't be used to separate data access permissions from job-running permissions.