How to Drop a Partition in ClickHouse
Last updated July 25, 2026 · By the SaturnSQL team
Use ALTER TABLE ... DROP PARTITION with the partition value, e.g. 202601 for a toYYYYMM key. Dropping a partition deletes its files directly, making it by far the cheapest way to remove bulk data, unlike DELETE which rewrites parts.
List partitions first
SELECT partition, sum(rows) AS rows,
formatReadableSize(sum(bytes_on_disk)) AS size
FROM system.parts
WHERE active AND table = 'events'
GROUP BY partition
ORDER BY partition;Drop one partition
ALTER TABLE events DROP PARTITION 202601;The partition value must match the PARTITION BY expression's output. Use DETACH PARTITION instead if you want the data moved aside and re-attachable rather than deleted.
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