使用python在mysql中插入字符串：未知列

Question

首先，我是一個初學者，我先感謝您的幫助:)

當我插入字符串時，它給我一個雙引號或單引號錯誤。這僅在我調用我創建的函數insert（）時發生。 但是，當我只用數字代替那些不帶引號的字符串時，它就起作用了。

import mysql.connector

conn = mysql.connector.connect(user="root",password='password',
       host='localhost',database='library',port='3306')
cur = conn.cursor()


def create_table():
    cur.execute("CREATE TABLE IF NOT EXISTS store 
               (id INT PRIMARY KEY, item VARCHAR(25), quantity INT, price REAL);")
    conn.commit()
    conn.close()


def insert(id, item, quantity, price):
    cur.execute("INSERT INTO store (id, quantity, price, item) 
                VALUES (%s, %s, %s, %s)" % (id, item, quantity, price))
    conn.commit()
    conn.close()



insert(50, 'test', 20, 10)

然后給出一個錯誤：

Traceback (most recent call last):
      File "C:\Program Files\Python36\lib\site- 
packages\mysql\connector\connection_cext.py", line 392, in cmd_query
        raw_as_string=raw_as_string)
    _mysql_connector.MySQLInterfaceError: Unknown column 'test' in 'field list'

    During handling of the above exception, another exception occurred:

    Traceback (most recent call last):
      File "C:\Users\Acer\Desktop\Remastered.py", line 128, in <module>
        insert(50, 'test', 20, 10)
      File "C:\Users\Acer\Desktop\Remastered.py", line 109, in insert
        cur.execute("INSERT INTO store (id, quantity, price, item) VALUES (%s, %s, %s, %s)" % (id, item, quantity, price))
      File "C:\Program Files\Python36\lib\site-packages\mysql\connector\cursor_cext.py", line 266, in execute
        raw_as_string=self._raw_as_string)
      File "C:\Program Files\Python36\lib\site-packages\mysql\connector\connection_cext.py", line 395, in cmd_query
        sqlstate=exc.sqlstate)
    mysql.connector.errors.ProgrammingError: 1054 (42S22): Unknown column 'test' in 'field list'
    [Finished in 0.8s with exit code 1]

Answer 1

您沒有正確使用占位符功能。 正確的行是：

cur.execute("INSERT INTO store (id, quantity, price, item) 
            VALUES (%s, %s, %s, %s)", (id, item, quantity, price))

注意, NOT %會造成嚴重的SQL注入錯誤 。

您的查詢已擴展為：

INSERT INTO store (...) VALUES (1, test, 1, 1.0);

如果沒有列出test部分，則將其視為可能的列名。

Answer 2

您已經混合了insert語句中的列順序，將“ INSERT INTO商店（id，數量，價格，項目）”更改為“ INSERT INTO商店（id，項目，數量，價格）”，請注意其中名為item的列是！ 導入mysql.connector

def create_table():
  cur.execute("CREATE TABLE IF NOT EXISTS store " \
           "(id INT PRIMARY KEY, item VARCHAR(25), quantity INT, price REAL);")
  conn.commit()
  return

def insert(id, item, quantity, price):
  cur.execute("INSERT INTO store (id, item, quantity, price)" \
            "VALUES (%s, '%s', %s, %s)" % (id, item, quantity, price))
  conn.commit()
  return

#
conn = mysql.connector.connect(user="root",
   host='localhost',database='DO',port='3306')
cur = conn.cursor()

create_table
insert(50, 'test', 20, 10)
insert(51, 'test', 20, 10)
insert(52, 'test', 20, 10)
conn.close()

從MySQL

mysql> select * from store;
+----+------+----------+-------+
| id | item | quantity | price |
+----+------+----------+-------+
| 50 | test |       20 |    10 |
| 51 | test |       20 |    10 |
| 52 | test |       20 |    10 |
+----+------+----------+-------+
3 rows in set (0.00 sec)

mysql>  INSERT INTO store (id, item, quantity, price) VALUES (53, 'test', 20, 10);
Query OK, 1 row affected (0.00 sec)

mysql> select * from store;
+----+------+----------+-------+
| id | item | quantity | price |
+----+------+----------+-------+
| 50 | test |       20 |    10 |
| 51 | test |       20 |    10 |
| 52 | test |       20 |    10 |
| 53 | test |       20 |    10 |
+----+------+----------+-------+
4 rows in set (0.00 sec)