Can't insert variable values into mysql database by using python

Recently,I've got a project that I need to save variable values into a database.

I want to program a code like this:

If I want to input username="Jonh", gender="Male", age=23, password="123456789", id="11111111"

then the code looks like:

#!/usr/bin/python
# -*- coding: UTF-8 -*-

import MySQLdb
import sys
db = MySQLdb.connect("140.120.31.124","usr1","606","testdb",port=3306 )

cursor = db.cursor()

urn="Jonh"
gdr="male"
agex="23"
psd="123456789"
idx="11111111"

sql = """INSERT INTO table1(username,gender,age,password,id) VALUES(%s,%s,%s,%s,%s)""" %(urn,gdr,agex,psd,idx)

#sql="""INSERT INTO table1(username,gender,age,password,id) VALUES("Jonh","male","23","123456789","11111111")"""

try:

   cursor.execute(sql)

   db.commit()
except Exception as inst:

   db.rollback()
   print inst

db.close()

The structure of database I set is:

username    varchar(50)     utf8_unicode_ci
gender      varchar(50)     utf8_unicode_ci 
age         int(2)          
password    varchar(20)     utf8_unicode_ci         
id          varchar(8)      utf8_unicode_ci     

But, it always shows the error --> (1054, "Unknown column 'Jonh' in 'field list'")

Does anyone can help me to solve this problem? Thanks a lot.

PS. The code I refer is https://www.packtpub.com/mapt/book/big_data_and_business_intelligence/9781849510189/3/ch03lvl1sec24/using-user-defined-variables