我在 Python 上使用 mysqlclient 运行查询时遇到问题。这是我所做的:
- 连接到数据库
- 通过 dict 循环查询
这是当我达到索引 16 时得到的结果:
_mysql_exceptions.OperationalError: (2013, 'Lost connection to MySQL server during query')
它在 Linux 上运行，但不在我的 Windows 环境中运行。
这个错误是什么？
这是我的代码和错误查询的位置
campaignsListReportData = {}
#Connect to Database
db = MySQLdb.connect('mysqlserver', 'user', 'password', 'selecteddb')
cursor = db.cursor()
query = """
SELECT
some column
FROM
some table
WHERE
some condition;
"""
cursor.execute(query)
data = cursor.fetchall()
for row in data:
campaignReport = {}
connectionState = False
while connectionState is False:
try:
url = "a URL"
r = requests.get(url, verify=False)
feedback = r.json()
if int(feedback['success']) is 0:
connectionState = True
elif int(feedback['success']) is 2:
connectionState = True
else:
cursor.execute("SELECT TRIM(SUM(counter)) FROM d WHERE a = " + str(row[1]))
counterURL = cursor.fetchone()
counterURLNumber = 0
if counterURL[0] == None:
counterURLNumber = 0
else:
counterURLNumber = counterURL[0]
urlData = []
cursor.execute("""SELECT long_url, counter , TRIM((counter / (SELECT SUM(counter) FROM d WHERE a = """ + str(row[1]) + """) * 100)) AS 'Percentage' """
"""FROM d """
"""WHERE c = """ + str(row[1]))
urlQuery = cursor.fetchall()
for row in urlQuery:
urlInfo = {
'label': row[0],
'value': row[1],
'percentage': row[2]
}
urlData.append(urlInfo)
campaignsListReportData[str(row[0])] = campaignReport
connectionState = True
except requests.exceptions.RequestException as e:
print(str(datetime.now() - timedelta(minutes=60)))
print("Connection Failed, Trying again . . .")
db.close()
错误发生于:
cursor.execute("SELECT TRIM(SUM(counter)) FROM d WHERE a = " + str(row[1]))
谢谢
最佳答案
尝试使用 cursor.execute("SELECT TRIM(SUM(counter)) FROM d WHERE a = %s", (str(row[]))) 内置函数 execute 有 2 个参数，第一个是要执行的查询，第二个是 %s 语句，因此我们可以将多个值传递给该选择。请记住，我们可以在一条语句中包含多个 %s，然后在第二个参数中传递值。了解更多 What does %s mean in Python?
关于Python mysql错误查询，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/45973399/