It is not required, but if you append an AS SELECT statement to the end of the previous SQL statement, then you have created a CETAS statement. You performed the COPY INTO exercise, which moves data from a data source in batches, in Exercise 4.13. You can see here how to use the COPY INTO command to bulk load a CSV file into a table. The data is batched into large datasets and placed into the table in a transmission that takes place very quickly.