Answer: CSV

The question asks about the default file format used in Snowflake's COPY command when no format is specified. According to Snowflake documentation and the community consensus (100% agreement with upvoted comments), CSV is the default file format. Comments like 'csv is default format' and 'A. CSV' with multiple upvotes confirm this. Other formats like JSON, Parquet, and XML require explicit specification in the COPY command and are not defaults.

Author: LeetQuiz Editorial Team