drop table if exists tab_00712_2; create table tab_00712_2 (a UInt32, b UInt32) engine = MergeTree order by b % 2 sample by b % 2; insert into tab_00712_2 values (1, 2), (1, 4); select a from tab_00712_2 sample 1 / 2 prewhere b = 2; drop table if exists tab_00712_2; DROP TABLE IF EXISTS sample_prewhere; CREATE TABLE sample_prewhere (CounterID UInt32, UserID UInt64) ENGINE = MergeTree ORDER BY UserID SAMPLE BY UserID; SELECT count() FROM sample_prewhere SAMPLE 1/2 PREWHERE CounterID = 1; DROP TABLE sample_prewhere;