Appending Data Export not working

Appending Data Export not working

I am trying to export data on an hourly basis from Zoho CRM to Zoho Analytics to Zoho dataprep then to a SQL Database.

I originally set up the export to Append the data but this deleted all data in my database and only exported the new rows, I then changed to overwrite but I am using way too many rows for this.

I need to change my export to Append the data going to the SQL Database. Can anyone help why this is happening?