engine : Null
initial comment
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = Null\nCOMMENT \'Test table with comment\'
comment=	Test table with comment

change a comment
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = Null\nCOMMENT \'new comment on a table\'
comment=	new comment on a table

remove a comment
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = Null
comment=	

add a comment back
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = Null\nCOMMENT \'another comment on a table\'
comment=	another comment on a table

detach table
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = Null\nCOMMENT \'another comment on a table\'

re-attach table
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = Null\nCOMMENT \'another comment on a table\'
comment=	another comment on a table

engine : Memory
initial comment
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = Memory\nCOMMENT \'Test table with comment\'
comment=	Test table with comment

change a comment
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = Memory\nCOMMENT \'new comment on a table\'
comment=	new comment on a table

remove a comment
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = Memory
comment=	

add a comment back
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = Memory\nCOMMENT \'another comment on a table\'
comment=	another comment on a table

detach table
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = Memory\nCOMMENT \'another comment on a table\'

re-attach table
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = Memory\nCOMMENT \'another comment on a table\'
comment=	another comment on a table

engine : MergeTree() ORDER BY k
initial comment
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = MergeTree\nORDER BY k\nSETTINGS index_granularity = 8192\nCOMMENT \'Test table with comment\'
comment=	Test table with comment

change a comment
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = MergeTree\nORDER BY k\nSETTINGS index_granularity = 8192\nCOMMENT \'new comment on a table\'
comment=	new comment on a table

remove a comment
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = MergeTree\nORDER BY k\nSETTINGS index_granularity = 8192
comment=	

add a comment back
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = MergeTree\nORDER BY k\nSETTINGS index_granularity = 8192\nCOMMENT \'another comment on a table\'
comment=	another comment on a table

detach table
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = MergeTree\nORDER BY k\nSETTINGS index_granularity = 8192\nCOMMENT \'another comment on a table\'

re-attach table
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = MergeTree\nORDER BY k\nSETTINGS index_granularity = 8192\nCOMMENT \'another comment on a table\'
comment=	another comment on a table

engine : Log
initial comment
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = Log\nCOMMENT \'Test table with comment\'
comment=	Test table with comment

change a comment
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = Log\nCOMMENT \'new comment on a table\'
comment=	new comment on a table

remove a comment
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = Log
comment=	

add a comment back
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = Log\nCOMMENT \'another comment on a table\'
comment=	another comment on a table

detach table
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = Log\nCOMMENT \'another comment on a table\'

re-attach table
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = Log\nCOMMENT \'another comment on a table\'
comment=	another comment on a table

engine : TinyLog
initial comment
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = TinyLog\nCOMMENT \'Test table with comment\'
comment=	Test table with comment

change a comment
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = TinyLog\nCOMMENT \'new comment on a table\'
comment=	new comment on a table

remove a comment
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = TinyLog
comment=	

add a comment back
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = TinyLog\nCOMMENT \'another comment on a table\'
comment=	another comment on a table

detach table
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = TinyLog\nCOMMENT \'another comment on a table\'

re-attach table
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = TinyLog\nCOMMENT \'another comment on a table\'
comment=	another comment on a table

engine : ReplicatedMergeTree('/clickhouse/02020_alter_table_modify_comment_default', '1') ORDER BY k
initial comment
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = ReplicatedMergeTree(\'/clickhouse/02020_alter_table_modify_comment_default\', \'1\')\nORDER BY k\nSETTINGS index_granularity = 8192\nCOMMENT \'Test table with comment\'
comment=	Test table with comment

change a comment
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = ReplicatedMergeTree(\'/clickhouse/02020_alter_table_modify_comment_default\', \'1\')\nORDER BY k\nSETTINGS index_granularity = 8192\nCOMMENT \'Test table with comment\'
comment=	Test table with comment

remove a comment
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = ReplicatedMergeTree(\'/clickhouse/02020_alter_table_modify_comment_default\', \'1\')\nORDER BY k\nSETTINGS index_granularity = 8192\nCOMMENT \'Test table with comment\'
comment=	Test table with comment

add a comment back
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = ReplicatedMergeTree(\'/clickhouse/02020_alter_table_modify_comment_default\', \'1\')\nORDER BY k\nSETTINGS index_granularity = 8192\nCOMMENT \'Test table with comment\'
comment=	Test table with comment

detach table
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = ReplicatedMergeTree(\'/clickhouse/02020_alter_table_modify_comment_default\', \'1\')\nORDER BY k\nSETTINGS index_granularity = 8192\nCOMMENT \'Test table with comment\'

re-attach table
CREATE TABLE default.comment_test_table\n(\n    `k` UInt64,\n    `s` String\n)\nENGINE = ReplicatedMergeTree(\'/clickhouse/02020_alter_table_modify_comment_default\', \'1\')\nORDER BY k\nSETTINGS index_granularity = 8192\nCOMMENT \'Test table with comment\'
comment=	Test table with comment