Unable to use mysql_upgrade: I updated mysql recently and found problem related to privileges and backup. When I am using mysql_upgrade command it says- 

mysqlcheck: Got error: 1064: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '.`'`  FOR UPGRADE' at line 1 when executing 'CHECK TABLE ...  FOR UPGRADE'


I searched this problem and found that this problem is due to use of delimeter in table_name and If I alter the name of table then this can be solved.
But I don't know how to search those table which are not ready to upgrade ?
Given that the valid characters for unquoted identifier characters are documented here, you should be able to find non-confirming table names in information_schema using a regular expression match, with this query:

SELECT * 
  FROM information_schema.tables
 WHERE table_name NOT RLIKE '^[0-9a-zA-Z$_]+$';