[GROUP BY] [ORDER BY] )` `-- 删除projection定义并且删除projection数据` `ALTER TABLE [db].table DROP PROJECTION name` `-- 物化原表的某个partition数据` `ALTER TABLE [db.]table MATERIALIZE PROJECTION name IN PARTITION partition_name` `-- 删除projection数据但不删除projection定义` `ALTER TABLE [db.]table CLEAR PROJECTION name IN PARTITION partition_name` ``` ...