text: DROP TABLE IF EXISTS check_comments;
  
  CREATE TABLE check_comments
    (
      column_name1 UInt8 DEFAULT 1 COMMENT 'comment',
      column_name2 UInt8 COMMENT 'non default comment'
    ) ENGINE = ReplicatedMergeTree('clickhouse/tables/test_00753/comments', 'r1')
      ORDER BY column_name1;
  
  SHOW CREATE check_comments;
  DESC check_comments;
  
  ALTER TABLE check_comments COMMENT COLUMN column_name1 'another comment';
  
  SHOW CREATE check_comments;
  DESC check_comments;
  
  SELECT * FROM system.columns WHERE table = 'check.comments' and database = currentDatabase();
  
  DROP TABLE check_comments;
  