其實也沒什麼難的，之前卡住了，寫個部落格以後備用

class A():

    def __init__(self):
        self.db = pymysql.connect(db='', host='localhost', port=3306, user='', passwd='',
                                  charset='utf8')
        self.cursor = self.db.cursor()
    def B(self,phone_user):
        sql = 'select * from `%s`' % (phone_user)
        self.cursor.execute(sql)
        rows = self.cursor.fetchall()
        objects_list = []
        for row in rows:
            d = collections.OrderedDict()
            d['cardnum'] = row[0]
            d['bankname'] = row[1]
            d['phonenumber'] = row[2]
            d['rest'] = row[3]
            d['id_main'] = row[4]
            objects_list.append(d)
         
        j = json.dumps(objects_list)
        return j