Python:MySQL 错误

Question

import MySQLdb    
import random

db = MySQLdb.connect (host = "localhost", user = "python-test", passwd = "python", db = "python-test")

cursor = db.cursor()

var = .3

sql = "INSERT INTO RandomInt 
         (RAND) 
       VALUES 
         (var)" # RandomInt is the name of the table and Rand is the Column Name

cursor.execute(sql)

db.commit()
db.close()

我收到一条错误消息说 Operational Error: (1054, "Unknown column 'var' in 'field list'") 为什么我会收到此错误以及如何解决此问题，尽管我已经定义变量？

Answer 1

如所写，var 将作为字符串发送到 MySQL。
试一试:

sql = "INSERT INTO RandomInt (RAND) VALUES (%s)"
cursor.execute(sql, (var,))

编辑:

>>> import MySQLdb
>>> MySQLdb.paramstyle
'format'

MySQLdb的paramstyle是format；其中，根据 DB-API是 %s:

            'format'        ANSI C printf format codes, 
                            e.g. '...WHERE name=%s'