左联接（LEFT JOIN）

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="myusername",
  passwd="mypassword",
  database="mydatabase"
)
 
mycursor = mydb.cursor()
 
sql = "SELECT \
  users.name AS user, \
  products.name AS favorite \
  FROM users \
  LEFT JOIN products ON users.fav = products.id"
 
mycursor.execute(sql)
 
myresult = mycursor.fetchall()
 
for x in myresult:
  print(x)