比较 mysql 中 python 的结果值未被采用

Question

我目前正在尝试比较 python

中设置为 mysql db 的值

下面是我的代码片段。

        def query():

            # CONNECTION TO THE DB.
            connection = pymysql.connect(host=host,
                                                     user=user,
                                                     password=pass1,
                                                     db=database,
                                                     charset='utf8mb4',
                                                     cursorclass=pymysql.cursors.DictCursor)
  with connection.cursor() as cursor:
                    logf.write(dateandtime + "- 3 - Getting the sensor value\n")
               # Fetch the sensor name
                    sql = "SELECT temp FROM expected_temp WHERE name = (select name from sensor where id = %s)"
                    cursor.execute(sql, (sens,))
                    result = cursor.fetchall()
                    for row in result:
                            na = "%s" % (row["temp"])
                            nam = str(na)
                            print (nam)

    if __name__ == '__main__':
    #Setup the GPIO
            GPIO.setmode(GPIO.BCM)
            GPIO.setwarnings(False)
            GPIO.setup(17,GPIO.OUT)

            try:
                    while True:
                            humidity, temperature = readAdafruitDHT('2302',17)
                            logf.write(dateandtime + "- 2 - Reading temperature\n")
                            target = query()
                            if temperature > target:
                                    print (dateandtime + ' - Current temperature: %f'  % temperature)
                                    logf.write(dateandtime + " - 3 - Current temperature: %f" % temperature + "\n")
                                    print (dateandtime + ' - Changing to HIGH')
                                    logf.write(dateandtime + ' - Changing to HIGH\n')
                                    GPIO.output(18,GPIO.HIGH)
                            else:
                                    print (dateandtime + ' - Current temperature: %f'  % temperature)
                                    logf.write(dateandtime + " - 3 - Current temperature: %f" % temperature + "\n")
                                    print (dateandtime + ' - Changing to LOW')
                                    logf.write(dateandtime + ' - Changing to LOW\n')
                                    GPIO.output(18,GPIO.LOW)
                            time.sleep(20)
            except KeyboardInterrupt:
                            GPIO.cleanup()
                            print("Bye")

所以，结果打印得很好，但我的条件不工作。看起来结果的值在比较完成时被视为值。

如有任何指导，我们将不胜感激。谢谢你们。乔.

Answer 1

万一它可能对其他人有帮助.. 我通过指定检索到的值的类型让操作员工作。

我更改了以下内容：

def query():

            # CONNECTION TO THE DB.
            connection = pymysql.connect(host=host,
                                                     user=user,
                                                     password=pass1,
                                                     db=database,
                                                     charset='utf8mb4',
                                                     cursorclass=pymysql.cursors.DictCursor)


            with connection.cursor() as cursor:
                    logf.write(dateandtime + "- 3 - Getting the sensor value\n")
               # Fetch the sensor name
                    sql = "SELECT temp FROM expected_temp WHERE name = (select name from sensor where id = %s)"
                    cursor.execute(sql, (sens,))
                    result = cursor.fetchall()
                    for row in result:
                            na = "%s" % (row["temp"])
                            nam = str(na)
                            #nam = float(na)
                            #n = nam.rstrip()
                            return int(nam)

    if __name__ == '__main__':
    #Setup the GPIO
            GPIO.setmode(GPIO.BCM)
            GPIO.setwarnings(False)
            GPIO.setup(17,GPIO.OUT)

            try:
                    while True:
                            humidity, temperature = readAdafruitDHT('2302',17)
                            logf.write(dateandtime + "- 2 - Reading temperature\n")
                            target = query()
                            print target
                            print (dateandtime, target)
                            if ( temperature > target ):
                                    print (dateandtime + ' - Current temperature: %f'  % temperature)
                                    logf.write(dateandtime + " - 3 - Current temperature: %f" % temperature + "\n")
                                    print (dateandtime + ' - Changing to HIGH')
                                    logf.write(dateandtime + ' - Changing to HIGH\n')
                                    GPIO.output(18,GPIO.HIGH)
                            else:
                                    print (dateandtime + ' - Current temperature: %f'  % temperature)
                                    logf.write(dateandtime + " - 3 - Current temperature: %f" % temperature + "\n")
                                    print (dateandtime + ' - Changing to LOW')
                                    logf.write(dateandtime + ' - Changing to LOW\n')
                                    GPIO.output(18,GPIO.LOW)
                            time.sleep(20)
            except KeyboardInterrupt:
                            GPIO.cleanup()
                            print("Bye")

无论如何谢谢你。乔.

比较 mysql 中 python 的结果值未被采用

comparing mysql result value in python not taken

python

mysql

variables

types

comparator