This column is automatically generated for JSON and CSV foreign tables if you do not explicitly specify any columns in the CREATE FOREIGN TABLE statement.
You can optionally specify a location column for foreign tables that have JSON and CSV data. If you specify a location column for these foreign tables, you must also specify a payload column.
The location column must have the following definition:
Location VARCHAR(2048) CHARACTER SET UNICODE CASESPECIFIC
You must specify a location column, but no payload column for foreign tables that have Parquet data.