DROP TABLE IF EXISTS table_with_pk_clear; CREATE TABLE table_with_pk_clear( key1 UInt64, key2 String, value1 String, value2 String ) ENGINE = MergeTree() ORDER by (key1, key2); INSERT INTO table_with_pk_clear SELECT number, number * number, toString(number), toString(number * number) FROM numbers(1000); ALTER TABLE table_with_pk_clear CLEAR COLUMN key1 IN PARTITION tuple(); --{serverError ALTER_OF_COLUMN_IS_FORBIDDEN} SELECT count(distinct key1) FROM table_with_pk_clear; ALTER TABLE table_with_pk_clear CLEAR COLUMN key2 IN PARTITION tuple(); --{serverError ALTER_OF_COLUMN_IS_FORBIDDEN} SELECT count(distinct key2) FROM table_with_pk_clear; DROP TABLE IF EXISTS table_with_pk_clear;