删除记录

您可以使用 "DELETE FROM" 语句从已有的表中删除记录：

示例代码：

删除地址为 "Mountain 21" 的任何记录：

import mysql.connector
mydb = mysql.connector.connect(
  host="localhost",
  user="yourusername",
  passwd="yourpassword",
  database="mydatabase"
)
mycursor = mydb.cursor()
sql = "DELETE FROM customers WHERE address = 'Mountain 21'"
mycursor.execute(sql)
mydb.commit()
print(mycursor.rowcount, "record(s) deleted")

完整实例：

import mysql.connector
mydb = mysql.connector.connect(
  host="localhost",
  user="myusername",
  passwd="mypassword",
  database="mydatabase"
)
mycursor = mydb.cursor()
sql = "SELECT * FROM customers WHERE address = 'Park Lane 38'"
mycursor.execute(sql)
myresult = mycursor.fetchall()
for x in myresult:
  print(x)

重要：请注意语句 mydb.commit()。需要进行更改，否则表不会有任何改变。

请注意 DELETE 语法中的 WHERE 子句：WHERE 子句指定应删除哪些记录。如果省略 WHERE 子句，则将删除所有记录！

防止 SQL 注入

在 delete 语句中，转义任何查询的值也是一种好习惯。

此举是为了防止 SQL 注入，这是一种常见的网络黑客技术，可以破坏或滥用您的数据库。

mysql.connector 模块使用占位符 ％s 来转义 delete 语句中的值：

示例代码：

使用占位符 ％s 方法来转义值：

import mysql.connector
mydb = mysql.connector.connect(
  host="localhost",
  user="yourusername",
  passwd="yourpassword",
  database="mydatabase"
)
mycursor = mydb.cursor()
sql = "DELETE FROM customers WHERE address = %s"
adr = ("Yellow Garden 2", )
mycursor.execute(sql, adr)
mydb.commit()
print(mycursor.rowcount, "record(s) deleted")

完整实例：

import mysql.connector
mydb = mysql.connector.connect(
  host="localhost",
  user="myusername",
  passwd="mypassword",
  database="mydatabase"
)
mycursor = mydb.cursor()
sql = "SELECT * FROM customers WHERE address = %s"
adr = ("Yellow Garden 2", )
mycursor.execute(sql, adr)
myresult = mycursor.fetchall()
for x in myresult:
  print(x)