python - 为什么这个查询不能从 python 到 SQL？

Question

我是编码和数据库的新手，如果我手写的话，我无法使查询工作，但我有很多事情要做，想在函数中使用它，但无法让它工作，它返回一个参数错误

import  mysql.connector

def connection_check_1(query, value):

    mydb = mysql.connector.connect(
        host="******",
        user="*****",
        passwd="*****",
        database="****"
    )

    mycursor = mydb.cursor()
    mycursor.execute(query, (value))
    myresult = mycursor.fetchall()
    mydb.close()
    return myresult

value = "sheep"
query = 'select inlicence from licence where animal = %s'
myresult = connection_check_1(query, value)
print(myresult)

这是我的 SQL 表

create table licence 
(
    animal varchar (20) primary key,
    inlicence int (1)
);

这是我得到的错误

Traceback (most recent call last):
File "*******************", line 20, in
myresult = connection_check_1(query, value)
File "********************", line 13, in connection_check_1
mycursor.execute(query, (value))
File "********************************************88", line 246, in execute
prepared = self._cnx.prepare_for_mysql(params)
File "/home/kev/PycharmProjects/test bed/venv/lib/python3.5/site-packages/mysql/connector/connection_cext.py", line 535, in prepare_for_mysql
raise ValueError("Could not process parameters")
ValueError: Could not process parameters

我尝试改变查询的编写方式，将其更改为fetchall()。

Answer 1

用 () 包装一个值不会将它变成一个元组。您可能打算在那里添加一个逗号:

mycursor.execute(query, (value,))
# Creates a one-element tuple-^