左联接(LEFT JOIN)
左联接(LEFT JOIN)详细操作教程
以下实例为学习左联接(LEFT JOIN),具体代码如下:
# Filename : example.py
# Author by : www.lidihuo.com
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)
执行以上代码输出结果为:
# Filename : example.py
# Author by : www.lidihuo.com
('John', 'Chocolate Heaven')
('Peter', 'Chocolate Heaven')
('Amy', 'Tasty Lemon')
('Hannah', None)
('Michael', None)