v.24.2Backward Incompatible Changes
Allow Parentheses in Alter Operations for Improved Query Clarity
Allow alter operations to be surrounded by parenthesis. The emission of parentheses can be controlled by theformat_alter_operations_with_parenthesesconfig. By default, in formatted queries the parentheses are emitted as we store the formatted alter operations in some places as metadata (e.g.: mutations). The new syntax clarifies some of the queries where alter operations end in a list. E.g.:ALTER TABLE x MODIFY TTL date GROUP BY a, b, DROP COLUMN ccannot be parsed properly with the old syntax. In the new syntax the queryALTER TABLE x (MODIFY TTL date GROUP BY a, b), (DROP COLUMN c)is obvious. Older versions are not able to read the new syntax, therefore using the new syntax might cause issues if newer and older version of ClickHouse are mixed in a single cluster. #59532 (János Benjamin Antal).