Failing SQL Feature:

The SAMPLE clause in ClickHouse lets you run a SELECT query on only a fraction of the data (a subset) to get fast approximate results by specifying a sample ratio or number.

Reproduce the issue with this query:

CREATE TABLE tmp.events
(
 id UInt64,
 user_id UInt32,
 timestamp DateTime
)
ENGINE = MergeTree()
ORDER BY id
SAMPLE BY id;
SELECT *
FROM events
SAMPLE 0.1;

Parsing error:

ParseException: Encountered: <K_SAMPLE> / "SAMPLE", at line 3, column 1, in lexical