Clarification on clustering, optimization, and storage

[ArockiyaJerson]

Hi Team,

1. Can we add clustering to any of the existing tables? If yes, will the clustering be applied to existing data in the table?

2. We have parquet files (~70 TB) which would be an efficient way to store the files concerning pricing irrespective of use case? Either GCS or BigQuery.

3. What are the best optimization approaches in BigQuery to save cost?

Any leads on this are much appreciated.

Thanks,

AJ