mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-09-21 17:20:50 +00:00
11 lines
526 B
SQL
11 lines
526 B
SQL
drop table if exists test.tab;
|
|
create table test.tab (a UInt32, b UInt32) engine = MergeTree order by b % 2 sample by b % 2;
|
|
insert into test.tab values (1, 2), (1, 4);
|
|
select a from test.tab sample 1 / 2 prewhere b = 2;
|
|
drop table if exists test.tab;
|
|
|
|
DROP TABLE IF EXISTS test.sample_prewhere;
|
|
CREATE TABLE test.sample_prewhere (CounterID UInt32, UserID UInt64) ENGINE = MergeTree ORDER BY UserID SAMPLE BY UserID;
|
|
SELECT count() FROM test.sample_prewhere SAMPLE 1/2 PREWHERE CounterID = 1;
|
|
DROP TABLE test.sample_prewhere;
|