mysql.connector.errors.ProgrammingError：处理格式参数失败； Python 'tuple' 无法转换为 MySQL 类型答案

【问题标题】：mysql.connector.errors.ProgrammingError: Failed processing format-parameters; Python 'tuple' cannot be converted to a MySQL typemysql.connector.errors.ProgrammingError：处理格式参数失败； Python 'tuple' 无法转换为 MySQL 类型
【发布时间】：2019-03-26 17:33:30
【问题描述】：

我是 Python 新手，只是找不到足够的这种模式的示例。运行 Python 3.4，安装了 MySQL Python 连接器。 MySQL 5.7 版。

使用这组代码（我已将用户、密码等的值替换为空格）：

import mysql.connector
cnx = mysql.connector.connect(user='', 
                        password='   ',
                        host='    ',
                        database='     ')
cursor = cnx.cursor()  
PortExistsQ = "SELECT Count(*) FROM portfolio WHERE idPortfolio=%s AND YearWeek(Signal_Date)=%s AND Rank=1"
cursor.execute(PortExistsQ,(portID,Yearweek))

我收到此错误。

Traceback (most recent call last):
  File "C:\Python34\lib\site-packages\mysql\connector\conversion.py", line 179, in to_mysql
    return getattr(self, "_{0}_to_mysql".format(type_name))(value)
AttributeError: 'MySQLConverter' object has no attribute '_tuple_to_mysql'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Python34\lib\site-packages\mysql\connector\cursor.py", line 417, in _process_params
    res = [to_mysql(i) for i in res]
  File "C:\Python34\lib\site-packages\mysql\connector\cursor.py", line 417, in <listcomp>
    res = [to_mysql(i) for i in res]
  File "C:\Python34\lib\site-packages\mysql\connector\conversion.py", line 182, in to_mysql
    "MySQL type".format(type_name))
TypeError: Python 'tuple' cannot be converted to a MySQL type

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Python34\lib\threading.py", line 920, in _bootstrap_inner
    self.run()
  File "C:\Python34\lib\threading.py", line 868, in run
    self._target(*self._args, **self._kwargs)
  File "C:\workspace\DIY Investing\CSI\CalcP.py", line 56, in calcport
    cursor.execute(PortExistsQ,(portID,Yearweek))
  File "C:\Python34\lib\site-packages\mysql\connector\cursor.py", line 539, in execute
    psub = _ParamSubstitutor(self._process_params(params))
  File "C:\Python34\lib\site-packages\mysql\connector\cursor.py", line 422, in _process_params
    "Failed processing format-parameters; %s" % err)
mysql.connector.errors.ProgrammingError: Failed processing format-parameters; Python 'tuple' cannot be converted to a MySQL type

SQL 在 MySQL Workbench 中按预期运行。如果 Portfolio 的值为 2，YearWeek 的值为 201644（导致错误的第一个值），MySQL 中的结果是 Count(*) of 1。

一个代码sn-p的

print ("Portfolio", portID, "YearWeek", Yearweek)

产生以下输出

Portfolio 2 YearWeek (201644,)

有什么建议吗？

【问题讨论】：

portID 和 Yearweek 的值是多少？
一个例子使用下面的代码sn-p。 print ("Portfolio", portID, "YearWeek", Yearweek)，生成以下打印行。投资组合 2 YearWeek (201644,)（作为导致错误的一个示例）。
你检查我的答案了吗？如果正确请不要忘记采纳。谢谢！

标签： python mysql

【解决方案1】：

错误说元组无法转换为 mysql 类型，当您执行 print 语句时，它变得相当明显

print ("Portfolio", portID, "YearWeek", Yearweek)
Produces the following output

Portfolio 2 YearWeek (201644,)

Yearweek 是一个元组，使用 Yearweek[0] 代替

【讨论】：

【解决方案2】：

根据您的示例 - Yearweek 是元组 (201644,)，您不能将元组用作准备好的语句的值。

您可以改用这个：

cursor.execute(PortExistsQ,(portID,Yearweek[0]))

或者

Yearweek = Yearweek[0]
cursor.execute(PortExistsQ,(portID,Yearweek))

这样传递给execute 函数的值是201644（它是元组中的第一个值），而不是元组本身。

【讨论】：