21. Unload to S3

-- Unload to external stage
COPY INTO @s3_stage/unload/
FROM my_table
FILE_FORMAT = (TYPE = PARQUET COMPRESSION = SNAPPY)
OVERWRITE = TRUE;

-- Partitioned unload
COPY INTO @s3_stage/unload/
FROM my_table
PARTITION BY ('dt=' || DATE(sale_date))
FILE_FORMAT = (TYPE = CSV)
HEADER = TRUE;

-- Validate unload
SELECT COUNT(*) FROM @s3_stage/unload/;

Unload Patterns

Best Practices

• Use OVERWRITE = TRUE for idempotent exports
• Add SINGLE = TRUE to get one file (not parallel)
• Set MAX_FILE_SIZE for file size control

COPY INTO @s3_stage/report.csv
FROM (SELECT * FROM my_table ORDER BY id)
FILE_FORMAT = (TYPE = CSV HEADER = TRUE)
SINGLE = TRUE
MAX_FILE_SIZE = 500000000;