CREATE TABLE distinct_cardinality_high (high UInt64, medium UInt64, low UInt64) ENGINE MergeTree() ORDER BY (high, medium) INSERT INTO distinct_cardinality_high SELECT number % 1e6, number % 1e4, number % 1e2 FROM numbers_mt(1e8) OPTIMIZE TABLE distinct_cardinality_high FINAL SELECT DISTINCT high FROM distinct_cardinality_high FORMAT Null SELECT DISTINCT high, medium FROM distinct_cardinality_high FORMAT Null SELECT DISTINCT high, medium FROM distinct_cardinality_high ORDER BY high, medium FORMAT Null SELECT DISTINCT high, medium FROM distinct_cardinality_high ORDER BY high FORMAT Null DROP TABLE IF EXISTS distinct_cardinality_high CREATE TABLE distinct_cardinality_low (low UInt64, medium UInt64, high UInt64) ENGINE MergeTree() ORDER BY (low, medium) INSERT INTO distinct_cardinality_low SELECT number % 1e2, number % 1e4, number % 1e6 FROM numbers_mt(1e8) OPTIMIZE TABLE distinct_cardinality_low FINAL SELECT DISTINCT low FROM distinct_cardinality_low FORMAT Null SELECT DISTINCT low, medium FROM distinct_cardinality_low FORMAT Null SELECT DISTINCT low, medium FROM distinct_cardinality_low ORDER BY low, medium FORMAT Null SELECT DISTINCT low, medium FROM distinct_cardinality_low ORDER BY low FORMAT Null DROP TABLE IF EXISTS distinct_cardinality_low