格式指定符不会被选择查询中的值替换从python传递到mysql

Question

我试图从python查询sql数据库。 当我直接在字符串中筛选过滤器的值并将i作为查询传递时，查询是合适的。然而，当我使用格式说明符像“％s”我正面临问题。

代码是如在此，如果我给％d为格式说明和= 2偶然后我面对错误如下

[import tkinter 
import tkinter.messagebox 
from tkinter import * 
import mysql.connector 

top = tkinter.Tk() 

#database connecion 
from mysql.connector import errorcode 
try: 
    cnx =mysql.connector.connect(host='localhost',user='root',password='1234') 
    cur = cnx.cursor() 
    query="CREATE DATABASE IF NOT EXISTS prj_db" 
    cur.execute(query) 
    cnx =mysql.connector.connect(host='localhost',database='prj_db',user='root',password='1234') 
except mysql.connector.Error as err: 
    if err.errno == errorcode.ER_ACCESS_DENIED_ERROR: 
    print("Something is wrong with your user name or password") 
    elif err.errno == errorcode.ER_BAD_DB_ERROR: 
    print("no db") 
    else: 
    print(err) 
else: 
    cur = cnx.cursor() 
    query = ("CREATE TABLE IF NOT EXISTS product_det_2" 
      "(P_id INT(4) UNSIGNED ZEROFILL NOT NULL AUTO_INCREMENT," 
      "P_name CHAR(20) DEFAULT '' NOT NULL," 
      "Drawing_num CHAR(20) DEFAULT '' NOT NULL," 
      "Price INT(4) UNSIGNED ZEROFILL NOT NULL," 
      "PRIMARY KEY(P_id))") 
    cur.execute(query) 
query = ("SELECT * FROM product_det_2") 
cur.execute(query) 
print(query) 
for (P_id, P_name, Drawing_num,Price) in cur: 
     print("{}, {}, {},{}".format(P_id, P_name, Drawing_num,Price)) 
print("*********************************") 
query = ("SELECT * FROM product_det_2 WHERE P_id=2") 
print(query) 
cur.execute(query) 
for (P_id, P_name, Drawing_num,Price) in cur: 
     print("{}, {}, {},{}".format(P_id, P_name, Drawing_num,Price)) 
print("*********************************") 
a="2" 
query = ("SELECT * FROM product_det_2 WHERE P_id=%s") 
print(query) 
cur.execute(query,a) 
for (P_id, P_name, Drawing_num,Price) in cur: 
     print("{}, {}, {},{}".format(P_id, P_name, Drawing_num,Price)) 
cnx.commit() 
top.mainloop()][1] 

。 请让我知道我错了enter image description here

Answer 1

的第二个参数cursor.execute()应该是一个元组或字典。即使只有一个参数插入到查询中，也是如此。试试这个：

cur.execute(query, (a,)) 

这里一个包含单个元素的元组被传递给​​。