创建数据库时报错 'str' object has no attribute 'decode'

python 版本3.6

django版本：2.2.2

建立数据库 python3 manage.py makemigrations的时候报错如下：

python3 manage.py makemigrations
Traceback (most recent call last):
File "manage.py", line 21, in <module>
main()
File "manage.py", line 17, in main
execute_from_command_line(sys.argv)
File "/usr/local/lib/python3.6/dist-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
utility.execute()
File "/usr/local/lib/python3.6/dist-packages/django/core/management/__init__.py", line 375, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/usr/local/lib/python3.6/dist-packages/django/core/management/base.py", line 323, in run_from_argv
self.execute(*args, **cmd_options)
File "/usr/local/lib/python3.6/dist-packages/django/core/management/base.py", line 364, in execute
output = self.handle(*args, **options)
File "/usr/local/lib/python3.6/dist-packages/django/core/management/base.py", line 83, in wrapped
res = handle_func(*args, **kwargs)
File "/usr/local/lib/python3.6/dist-packages/django/core/management/commands/makemigrations.py", line 101, in handle
loader.check_consistent_history(connection)
File "/usr/local/lib/python3.6/dist-packages/django/db/migrations/loader.py", line 283, in check_consistent_history
applied = recorder.applied_migrations()
File "/usr/local/lib/python3.6/dist-packages/django/db/migrations/recorder.py", line 73, in applied_migrations
if self.has_table():
File "/usr/local/lib/python3.6/dist-packages/django/db/migrations/recorder.py", line 56, in has_table
return self.Migration._meta.db_table in self.connection.introspection.table_names(self.connection.cursor())
File "/usr/local/lib/python3.6/dist-packages/django/db/backends/base/base.py", line 256, in cursor
return self._cursor()
File "/usr/local/lib/python3.6/dist-packages/django/db/backends/base/base.py", line 233, in _cursor
self.ensure_connection()
File "/usr/local/lib/python3.6/dist-packages/django/db/backends/base/base.py", line 217, in ensure_connection
self.connect()
File "/usr/local/lib/python3.6/dist-packages/django/db/backends/base/base.py", line 197, in connect
self.init_connection_state()
File "/usr/local/lib/python3.6/dist-packages/django/db/backends/mysql/base.py", line 231, in init_connection_state
if self.features.is_sql_auto_is_null_enabled:
File "/usr/local/lib/python3.6/dist-packages/django/utils/functional.py", line 80, in __get__
res = instance.__dict__[self.name] = self.func(instance)
File "/usr/local/lib/python3.6/dist-packages/django/db/backends/mysql/features.py", line 82, in is_sql_auto_is_null_enabled
cursor.execute('SELECT @@SQL_AUTO_IS_NULL')
File "/usr/local/lib/python3.6/dist-packages/django/db/backends/utils.py", line 103, in execute
sql = self.db.ops.last_executed_query(self.cursor, sql, params)
File "/usr/local/lib/python3.6/dist-packages/django/db/backends/mysql/operations.py", line 146, in last_executed_query
query = query.decode(errors='replace')
AttributeError: 'str' object has no attribute 'decode'

查看代码operations.py  146 行：

if query is not None:
    query = query.decode(errors='replace')  //这个是str 编码到byte，所以该写成 query.encode(errors='replace') 
return query