mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-09-21 17:20:50 +00:00
50 lines
2.0 KiB
SQL
50 lines
2.0 KiB
SQL
drop table if exists xy;
|
|
|
|
create table xy(x int, y int) engine MergeTree partition by intHash64(x) % 2 order by y settings index_granularity = 1;
|
|
|
|
-- intHash64(0) % 2 = 0
|
|
-- intHash64(2) % 2 = 1
|
|
-- intHash64(8) % 2 = 0
|
|
-- intHash64(9) % 2 = 1
|
|
insert into xy values (0, 2), (2, 3), (8, 4), (9, 5);
|
|
|
|
-- Now we have two partitions: 0 and 1, each of which contains 2 values.
|
|
-- minmax index for the first partition is 0 <= x <= 8
|
|
-- minmax index for the second partition is 2 <= x <= 9
|
|
|
|
SET max_rows_to_read = 2;
|
|
|
|
select * from xy where intHash64(x) % 2 = intHash64(2) % 2;
|
|
|
|
-- Equality is another special operator that can be treated as an always monotonic indicator for deterministic functions.
|
|
-- minmax index is not enough.
|
|
select * from xy where x = 8;
|
|
|
|
drop table if exists xy;
|
|
|
|
-- Test if we provide enough columns to generate a partition value
|
|
drop table if exists xyz;
|
|
create table xyz(x int, y int, z int) engine MergeTree partition by if(toUInt8(x), y, z) order by x settings index_granularity = 1;
|
|
insert into xyz values (1, 2, 3);
|
|
select * from xyz where y = 2;
|
|
drop table if exists xyz;
|
|
|
|
-- Test if we obey strict rules when facing NOT contitions
|
|
drop table if exists test;
|
|
create table test(d Date, k Int64, s String) Engine=MergeTree partition by (toYYYYMM(d),k) order by (d, k);
|
|
|
|
insert into test values ('2020-01-01', 1, '');
|
|
insert into test values ('2020-01-02', 1, '');
|
|
|
|
select * from test where d != '2020-01-01';
|
|
drop table test;
|
|
|
|
-- Test if single value partition pruning works correctly for Date = String
|
|
drop table if exists myTable;
|
|
CREATE TABLE myTable (myDay Date, myOrder Int32, someData String) ENGINE = ReplacingMergeTree PARTITION BY floor(toYYYYMMDD(myDay), -1) ORDER BY (myOrder);
|
|
INSERT INTO myTable (myDay, myOrder) VALUES ('2021-01-01', 1);
|
|
INSERT INTO myTable (myDay, myOrder) VALUES ('2021-01-02', 2); // This row should be returned
|
|
INSERT INTO myTable (myDay, myOrder) VALUES ('2021-01-03', 3);
|
|
SELECT * FROM myTable mt WHERE myDay = '2021-01-02';
|
|
drop table myTable;
|