Appflow SAP - How to have a created_at column in Redshift table

Hi Community,

I'm trying to extract data from the SAP data source to a Redshift table. I tried to add a created_at column to the Redshift table with the default current timestamp value, but this column always has a value is NULL. As I know, the reason is the COPY command of Appflow from S3 to Redshift does not have a list of specific columns in the target table.

So how can I know the time rows in the Redshift table inserted into?