从表中选择记录时,可以使用 "WHERE" 语句对选择进行筛选:
选择记录为 "Park Lane 38" 的记录,结果:
import mysql.connectormydb = 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)
您也可以选择以给定字母或短语开头、包含或结束的记录。
请使用 % 表示通配符:
选择地址中包含单词 "way" 的记录:
import mysql.connectormydb = 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)
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:
使用占位符 %s 方法来转义查询值:
import mysql.connectormydb = 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)