Django2.2报错 AttributeError: 'str' object has no attribute 'decode'

准备将 Django 连接到 MySQL，在命令行输入命令 python manage.py makemigrations 后报错： AttributeError: 'str' object has no attribute 'decode'
出现这个错误之后可以根据错误提示找到文件位置，打开 operations.py 文件，找到以下代码：

def last_executed_query(self, cursor, sql, params):
    # With MySQLdb, cursor objects have an (undocumented) "_executed"
    # attribute where the exact query sent to the database is saved.
    # See MySQLdb/cursors.py in the source distribution.
    query = getattr(cursor, '_executed', None)
    if query is not None:
        query = query.decode(errors='replace')
    return query

根据错误信息提示，说明 if 语句执行时出错， query 是 str 类型，而 decode() 是用来将 bytes 转换成 string 类型用的，（关于Python编码点这里），由于 query 不需要解码，所以直接将 if 语句注释掉就可以了

def last_executed_query(self, cursor, sql, params):
    # With MySQLdb, cursor objects have an (undocumented) "_executed"
    # attribute where the exact query sent to the database is saved.
    # See MySQLdb/cursors.py in the source distribution.
    query = getattr(cursor, '_executed', None)
    # if query is not None:
    #     query = query.decode(errors='replace')
    return query