DROP TABLE IF EXISTS prop_table; CREATE TABLE prop_table ( column_default UInt64 DEFAULT 42, column_materialized UInt64 MATERIALIZED column_default * 42, column_alias UInt64 ALIAS column_default + 1, column_codec String CODEC(ZSTD(10)), column_comment Date COMMENT 'Some comment', column_ttl UInt64 TTL column_comment + INTERVAL 1 MONTH ) ENGINE MergeTree() ORDER BY tuple() TTL column_comment + INTERVAL 2 MONTH; SHOW CREATE TABLE prop_table; SYSTEM STOP TTL MERGES prop_table; INSERT INTO prop_table (column_codec, column_comment, column_ttl) VALUES ('str', toDate('2019-10-01'), 1); SELECT column_default, column_materialized, column_alias, column_codec, column_comment, column_ttl FROM prop_table; ALTER TABLE prop_table MODIFY COLUMN column_comment REMOVE COMMENT; SHOW CREATE TABLE prop_table; ALTER TABLE prop_table MODIFY COLUMN column_codec REMOVE CODEC; SHOW CREATE TABLE prop_table; ALTER TABLE prop_table MODIFY COLUMN column_alias REMOVE ALIAS; SELECT column_default, column_materialized, column_alias, column_codec, column_comment, column_ttl FROM prop_table; SHOW CREATE TABLE prop_table; INSERT INTO prop_table (column_alias, column_codec, column_comment, column_ttl) VALUES (33, 'trs', toDate('2020-01-01'), 2); SELECT column_default, column_materialized, column_alias, column_codec, column_comment, column_ttl FROM prop_table ORDER BY column_ttl; ALTER TABLE prop_table MODIFY COLUMN column_materialized REMOVE MATERIALIZED; SHOW CREATE TABLE prop_table; INSERT INTO prop_table (column_materialized, column_alias, column_codec, column_comment, column_ttl) VALUES (11, 44, 'rts', toDate('2020-02-01'), 3); SELECT column_default, column_materialized, column_alias, column_codec, column_comment, column_ttl FROM prop_table ORDER BY column_ttl; ALTER TABLE prop_table MODIFY COLUMN column_default REMOVE DEFAULT; SHOW CREATE TABLE prop_table; INSERT INTO prop_table (column_materialized, column_alias, column_codec, column_comment, column_ttl) VALUES (22, 55, 'tsr', toDate('2020-03-01'), 4); SELECT column_default, column_materialized, column_alias, column_codec, column_comment, column_ttl FROM prop_table ORDER BY column_ttl; ALTER TABLE prop_table REMOVE TTL; SHOW CREATE TABLE prop_table; ALTER TABLE prop_table MODIFY COLUMN column_ttl REMOVE TTL; SHOW CREATE TABLE prop_table; SYSTEM START TTL MERGES prop_table; OPTIMIZE TABLE prop_table FINAL; SELECT COUNT() FROM prop_table; DROP TABLE IF EXISTS prop_table;