The value of the PARTITION_COMMENT column is an empty string if there is no partition comment.


mysql-test/r/information_schema_part.result:
  result fix
mysql-test/r/ndb_dd_alter.result:
  result fix
mysql-test/r/ndb_dd_backuprestore.result:
  result fix
mysql-test/r/ndb_partition_range.result:
  result fix
sql/sql_show.cc:
  The value of the PARTITION_COMMENT column is an empty string if there is no partition comment.