You need to select a method of moving data from the staging tables to the factOrders table. What type of Transact-SQL (T-SQL) statement should you use?

INSERT INTO...SELECT physically copies rows one at a time within a transaction, which is slow for large fact table loads and does not leverage partition architecture.

SELECT...INTO creates a brand-new table from a query result and cannot insert data into an existing fact table.

ALTER PARTITION-SWITCH is not valid T-SQL syntax; the correct statement for a partition switch is ALTER TABLE...SWITCH.

ALTER PARTITION FUNCTION adds or removes a boundary point to change the number of partitions in a partition function, and does not move data between tables.

ALTER TABLE...SWITCH reassigns a partition or an entire table to a target partition by updating metadata only, without physically moving rows, which makes it extremely fast for loading large volumes of staged data into a fact table. This is the standard ETL pattern for loading data warehouse fact tables because it avoids full table scans and row-by-row inserts. The staging table must match the structure and constraints of the target partition for the switch to succeed.