mariaDB：列计数与第 1 行的值计数不匹配

Question

我不明白这里有什么问题。我想构建一个网络爬虫来抓取亚马逊并将价格和名称输入数据库。但由于某种原因，它告诉我列和值不匹配。我的数据库中确实有一个名为“时间戳”的附加列，我在其中自动输入时间，但这是由数据库处理的。我正在使用 MariaDB。一位朋友说我也可以使用 MySQL API for MariaDB。

附： preis = price，来自德国，有时会在英语和德语之间切换，以防万一有人想知道。

import requests, time, csv, pymysql
from bs4 import BeautifulSoup as bs

#URL = input("URL")
URL = "https://www.amazon.de/gp/product/B075FTXF15/ref=crt_ewc_img_bw_3?ie=UTF8&psc=1&smid=A24FLB4J0NZBNT"
def SOUPIT (tempURL):
    URL = tempURL
    page = requests.get(URL,headers={"User-Agent":"Defined"})
    soup = bs(page.content, "html.parser")

    raw_price = soup.find(id="priceblock_ourprice").get_text()
    price = raw_price[:-2]


    raw_name = soup.find(id="productTitle").get_text()
    name = raw_name.strip()

    for i in range(0,len(name)-1):
        if name[i] == "(":
            name = name[:i]
            break
    data = [name, price, time.strftime("%H:%M:%S"), time.strftime("%d.%m.%Y")]

    return(data)

data = SOUPIT(URL)

while True:

    data = SOUPIT(URL)

    db = pymysql.connect("localhost", "root", "root", "test")
    cursor = db.cursor()

    if (data == None):
        break
        print("break")
    else:
        name = data[0]
        preis = data[1]
        sql = """INSERT INTO amazon_preise (Name, Preis) VALUES ('{}',{})""".format(name,preis)
        cursor.execute(sql)
        db.commit()
        print("success")

    print(data)
    time.sleep(60)

错误信息：

Traceback (most recent call last):
  File "amazonscraper_advanced.py", line 43, in <module>
    cursor.execute(sql)
  File "C:\Users\...\AppData\Local\Programs\Python\Python36\lib\site-packages\pymysql\cursors.py", line 170, in execute
    result = self._query(query)
  File "C:\Users\...\AppData\Local\Programs\Python\Python36\lib\site-packages\pymysql\cursors.py", line 328, in _query
    conn.query(q)
  File "C:\Users\...\AppData\Local\Programs\Python\Python36\lib\site-packages\pymysql\connections.py", line 517, in query
    self._affected_rows = self._read_query_result(unbuffered=unbuffered)
  File "C:\Users\...\AppData\Local\Programs\Python\Python36\lib\site-packages\pymysql\connections.py", line 732, in _read_query_result
    result.read()
  File "C:\Users\...\AppData\Local\Programs\Python\Python36\lib\site-packages\pymysql\connections.py", line 1075, in read
    first_packet = self.connection._read_packet()
  File "C:\Users\...\AppData\Local\Programs\Python\Python36\lib\site-packages\pymysql\connections.py", line 684, in _read_packet
    packet.check_error()
  File "C:\Users\...\AppData\Local\Programs\Python\Python36\lib\site-packages\pymysql\protocol.py", line 220, in check_error
    err.raise_mysql_exception(self._data)
  File "C:\Users\...\AppData\Local\Programs\Python\Python36\lib\site-packages\pymysql\err.py", line 109, in raise_mysql_exception
    raise errorclass(errno, errval)
pymysql.err.InternalError: (1136, "Column count doesn't match value count at row 1")

Answer 1

问题至少部分是由使用字符串格式将值插入 SQL 语句引起的。

这是抓取的数据：

>>> data = ['Sweatshirt Alien VS. Predator Z100088', '32,99', '14:08:43', '08.09.2019']
>>> name, preis, *_ = data

让我们创建 SQL 语句

>>> sql = """INSERT INTO amazon_preise (Name, Preis) VALUES ('{}',{})""".format(name,preis)

并显示它：

>>> sql
"INSERT INTO amazon_preise (Name, Preis) VALUES ('Sweatshirt Alien VS. Predator Z100088',32,99)"

注意VALUES 子句包含三个逗号分隔值；这是因为网页以德国风格显示货币，即用逗号分隔美分和欧元。当插入到 SQL 语句中时 preis 变成两个值而不是一个。

解决此问题的正确方法是将preis 从字符串转换为浮点数或小数，并使用参数替换而不是字符串格式来插入值。..

>>> fpreis = float(preis.replace(',', '.'))
>>> sql = """INSERT INTO amazon_preise (Name, Preis) VALUES (%s, %s)"""
>>> cursor.execute(sql, (name, fpreis))