class ActiveRecord::ConnectionAdapters::AbstractMysqlAdapter

def table_comment(table_name) # :nodoc:
  scope = quoted_scope(table_name)
  query_value(<<~SQL, "SCHEMA").presence
    SELECT table_comment
    FROM information_schema.tables
    WHERE table_schema = #{scope[:schema]}
      AND table_name = #{scope[:name]}
  SQL
end