Python MySQL Where

Use a filter to select

When selecting records from a table, you can use the "WHERE" statement to filter the selection:

实例

Select records for "Park Lane 38", results:

import mysql.connector
mydb = mysql.connector.connect(
  host="localhost",
  user="yourusername",
  passwd="yourpassword",
  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)

运行实例

Wildcard

You can also choose records that start with, contain, or end with a given letter or phrase.

Please use % Represents the wildcard:

实例

Select records containing the word "way" in the address:

import mysql.connector
mydb = mysql.connector.connect(
  host="localhost",
  user="yourusername",
  passwd="yourpassword",
  database="mydatabase"
)
mycursor = mydb.cursor()
sql = "SELECT * FROM customers WHERE address LIKE '"%way%"
mycursor.execute(sql)
myresult = mycursor.fetchall()
for x in myresult:
  print(x)

运行实例

防止 SQL 注入

当用户提供查询值时，您应该转义这些值。

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 模块拥有转义查询值的方法：

实例

使用占位符 ％s 方法来转义查询值：

import mysql.connector
mydb = mysql.connector.connect(
  host="localhost",
  user="yourusername",
  passwd="yourpassword",
  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)

运行实例