Final answer:
The default data format Sqoop uses to export data to a relational database is CSV (Comma-Separated Values). Sqoop is a tool for transferring data between relational databases and Hadoop, and it uses the CSV format for export operations by default.
Step-by-step explanation:
The default data format Sqoop uses to export data to a database is CSV (Comma-Separated Values). Sqoop is a command-line interface application for transferring data between relational databases and Hadoop. It imports data from a relational database to Hadoop Distributed File System (HDFS), and exports data from HDFS back to the relational database. When exporting, Sqoop converts the data into text files with fields delimited by commas by default, which aligns with the CSV file format. While Sqoop also supports other data formats like Avro, Parquet, and JSON for import operations, CSV remains the default for export operations unless specified otherwise through Sqoop's command-line options.