What is External Tables?

External tables are database objects that allow you to access data stored outside of the database itself, as if it were a regular table. They are commonly used to query data residing in files (like CSV, Parquet, JSON, etc.) on cloud storage (like AWS S3, Azure Blob Storage, Google Cloud Storage) or on network file systems. This avoids the need to load the data into the database before querying it, which can be useful for large datasets or infrequently accessed data. They can also serve as a mechanism to integrate data from disparate systems. Some database systems may also utilize external tables for data warehousing purposes.