A company has an existing Redshift table which contains all the order information for a product for historical analysis. Now there is a requirement to add more data to this table. Which of the following is the most efficient way to achieve this?

Answer options:

A.Use a Batch insert command
B.Make use of staging table
C.Execute the merge command with the new rows
D.Execute the upsert command with the new rows

Answer - B
The AWS Documentation mentions the following
You can efficiently add new data to an existing table by using a combination of updates and inserts from a staging table. While Amazon Redshift does not support a single merge, or upsert, command to update a table from a single data source, you can perform a merge operation by creating a staging table and then using one of the methods described in this section to update the target table from the staging table.
For more information on using staging tables, please refer to the below URL
https://docs.aws.amazon.com/redshift/latest/dg/t_updating-inserting-using-staging-tables-.html