PYODBC 不喜欢 %，“SQL 包含 2 个参数标记，但提供了 1 个参数." [英] PYODBC does not like %, "The SQL contains 2 parameter markers, but 1 parameters were supplied."

问题描述

所以我目前正在将 Python 与 SQL 联系起来以提取客户信息.不幸的是，我遇到了一些关于 SQL 的错误.我正在尝试使用 LIKE 运算符和 % 通配符，但由于 Python 不喜欢 %.结果，它假装 %s 之间的变量不存在.这就是我的意思:

So I'm currently linking Python with SQL to pull out customer information. Unfortunately, I'm getting some errors with regards to SQL. I am trying to use the LIKE operator, and the % wildcard, but I keep getting errors because Python does not like %. As a result, it pretends that variable between the %s do not exist. Here's what I mean:

SELECT custnbr,
       firstname,
       middleint,
       lastname
FROM   lqppcusmst
WHERE  custnbr = ?  AND firstname LIKE ? 

现在，我只是在测试它，所以我只使用客户编号和名字.我给它一个值:

Right now, I'm just testing it out, so I'm just using the customer number, and the first name. I give it a value:

remote_system_account_number = request.DATA['remote_system_account_number']
remote_system_first_name = request.DATA['remote_system_first_name']

因为我写的是在数据库中搜索客户，所以可能会有空白条目，所以我是这样的:

Since what I'm writing is for searching customers within the database, there's a chance there could be blank entries, so I have it like such:

if remote_system_account_number != '':
    SQL_where += ' custnbr = ? '
    parameters += "remote_system_account_number"
if remote_system_first_name != '':
    SQL_where += ' AND firstname LIKE ? '
    parameters += ", %remote_system_first_name%"

所以我认为这会奏效，但没有.当我像这样执行它时:

So I thought this would work, but it didn't. When I execute it like such:

database_cursor.execute(customer_information_SQLString + SQL_where, parameters)

我明白了:

ProgrammingError: ('The SQL contains 2 parameter markers, but 1 parameters were supplied', 'HY000')

有人知道怎么处理吗?

推荐答案

parameters 不应该是逗号分隔的字符串，它应该是具有多个值匹配的可枚举(列表或类似)SQL 中占位符的数量.例如:

parameters should not be a comma separated string, it should be an enumerable (a list or similar) with a number of values matching the number of placeholders in your SQL. For instance:

parameters = []
if remote_system_account_number != '':
    SQL_where += ' custnbr = ? '
    parameters.append("remote_system_account_number")
if remote_system_first_name != '':
    SQL_where += ' AND firstname LIKE ? '
    parameters.append("%remote_system_first_name%")

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