python - 使用 Python 从 MySQLdb 中提取条目

Question

我正在尝试使用 Python 连接到 MySQL 数据库，查询一个字段的值，如果它与预定义值匹配则返回。

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

import MySQLdb as mdb

con = mdb.connect('localhost', 'user', 'pass', 'db');
with con: 
    cur = con.cursor()
    cur.execute("SELECT * FROM tablename")
    rows = cur.fetchone()
    for row in rows:
        print row

这是我到目前为止所拥有的，它返回一个类似于(0L，用户名字段，密码字段，字段3)的值。我如何添加到此代码，以便我可以指定提取条目 WHERE user = "therightuser"AND pass = "therightpass"，然后从该条目提取 field3 的值。类似于...

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

import MySQLdb as mdb

con = mdb.connect('localhost', 'user', 'pass', 'db');
with con: 
    cur = con.cursor()
    cur.execute("SELECT * FROM table name WHERE user ='therightuser' AND pass ='therightpass'")
    rows = cur.fetchone()
    for row in rows:
        print row[field3]
    if field3 == "yes":
            print ("The field says yes")
    else:
            print ("The field says no")

Answer 1

尝试以下操作:

cur.execute("SELECT * FROM table name WHERE user ='therightuser' AND pass ='therightpass'")
    row = cur.fetchone()
    print row[3]
    if field3 == "yes":
            print ("The field says yes")
    else:
            print ("The field says no")

或者，更安全的实现是:

cur.execute("""SELECT * FROM table name WHERE user=%s AND pass=%s""", ('therightuser', 'therightpass'))

如果您希望能够通过列名称访问数据，即 打印row['field3']，可以使用以下方法:

def FetchOneAssoc(cursor) :
    data = cursor.fetchone()
    if data == None :
        return None
    desc = cursor.description

    dict = {}

    for (name, value) in zip(desc, data) :
        dict[name[0]] = value

    return dict

因此，在 cur.execute(...) 之后，您将拥有:

row = FetchOneAssoc(cur)
print row['field3']

引用http://www.ianhowson.com/a-quick-guide-to-using-mysql-in-python.html