thevar1able/ClickHouse
1
0
Fork 0
mirror of https://github.com/ClickHouse/ClickHouse.git synced 2024-09-29 05:00:47 +00:00
Code Issues Packages Projects Releases Wiki Activity
15d50d4581
ClickHouse/docs/en/sql-reference/statements/alter/sample-by.md
Amos Bird 078b14610d
ALTER MODIFY SAMPLE BY
2020-08-27 22:31:30 +08:00

754 B
Raw Blame History

toc_priority toc_title
41 SAMPLE BY

Manipulating Sampling-Key Expressions

ALTER TABLE [db].name [ON CLUSTER cluster] MODIFY SAMPLE BY new_expression

The command changes the sampling key of the table to new_expression (an expression or a tuple of expressions).

The command is lightweight in a sense that it only changes metadata. The primary key must contain the new sample key.

!!! note "Note" It only works for tables in the MergeTree family (including replicated tables).