为什么 PyMySQL 查询没有给出任何输出? [英] Why is the PyMySQL query not giving any output?

问题描述

我的代码如下-

import pymysql
connection = pymysql.connect(host='localhost',user='root',password='',db='form',charset='utf8mb4',cursorclass=pymysql.cursors.DictCursor)

try:
    with connection.cursor() as cursor:
        # Create a new record
        sql = "SELECT * FROM info ORDER BY `id` DESC LIMIT 1"
        cursor.execute(sql)

finally:
        connection.close()

语法正确，但没有输出任何内容.终端只是打开另一个提示.我的桌子是

The syntax is correct, but it isn't outputting anything. Terminal simply opens another prompt. My table is

email                  username                       id
[e-mail]          usrname1                        1
[e-mail]         usrname2                        2

所需的输出是

[e-mail]              usrname2

我哪里出错了?

推荐答案

我希望这将有助于用您自己的凭据替换所有凭据:

I hope this will help replace all credential with your own one:

您的代码中缺少的是您正在执行查询的打印语句，但没有对其进行任何操作，请查看 connection.commit() 语句之后的代码.这是有关如何使用 pyMySQL

What you are missing in your code is a print statement you are executing a query, but not doing anything with it, take a look at the code that is after the connection.commit() statement. Here is documentation and example on how to use pyMySQL

import pymysql.cursors


# Connect to the database
connection = pymysql.connect(host='localhost',
                             user='user',
                             password='passwd',
                             db='db',
                             charset='utf8mb4',
                             cursorclass=pymysql.cursors.DictCursor)

try:
    with connection.cursor() as cursor:
        # Create a new record
        sql = "INSERT INTO `users` (`email`, `password`) VALUES (%s, %s)"
        cursor.execute(sql, ('[e-mail]', 'very-secret'))

    # connection is not autocommit by default. So you must commit to save
    # your changes.
    connection.commit()

    with connection.cursor() as cursor:
        # Read a single record
        sql = "SELECT `id`, `password` FROM `users` WHERE `email`=%s"
        cursor.execute(sql, ('[e-mail]',))
        result = cursor.fetchone()
        print(result)
finally:
    connection.close()

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