Comprehensive and Detailed in Depth

Why C is correct:Materialized views in BigQuery are precomputed views that periodically cache the

results of a query. This ensures up-to-date results automatically.

A UNION is the correct operation to combine the data from multiple regional sales tables.

RANK() function is correct to rank the sales regions. ROW_NUMBER() would create a unique number

for each row, even if sales amount is the same, this is not the desired function.

Why other options are incorrect:A and B: Standard tables do not provide automatic updates.

D: A CROSS JOIN would produce a Cartesian product, which is not appropriate for combining regional

sales data.

Cross join is used when you want every combination of rows from tables, not a aggregation of data.

Reference:

BigQuery Materialized Views: https://cloud.google.com/bigquery/docs/materialized-views

BigQuery Window Functions: https://cloud.google.com/bigquery/docs/reference/standardsql/window-functions

BigQuery UNION: https://cloud.google.com/bigquery/docs/reference/standard-sql/querysyntax#union_all

BigQuery CROSS JOIN: https://cloud.google.com/bigquery/docs/reference/standard-sql/querysyntax#cross_join