在python中，是否有一个函数来增加日期和时间，同时声明时间范围？

我们正在用python进行一个项目，其中数据存储在MySQL数据库中。在数据库中，我们有两个表，其中表1（原始数据）接收来自2个不同来源（LPN1、RisingHF）的数据，表2（气象站）从一个来源存储数据

我们要做的是减去值，例如：

For 2019-07-26 15:00:00 to 2019-07-26 15:20:00
subtract latest data received from weather station with LPN1
subtract latest data received from weather station with RisingHF

For 2019-07-26 15:20:00 to 2019-07-26 15:40:00
subtract latest data received from weather station with LPN1
subtract latest data received from weather station with RisingHF

For 2019-07-26 15:40:00 to 2019-07-26 16:00:00
subtract latest data received from weather station with LPN1
subtract latest data received from weather station with RisingHF

import pandas as pd
from pandas.io import sql
from sqlalchemy import create_engine

list_lpn = []
list_rising = []

engine = create_engine("mysql://xxx:xxx@localhost/xxx")

conn = engine.connect()
    for x in range (24):
        for y in range (0, 20, 40):
            a = pd.read.sql("SELECT MAX(timestamp) FROM Weather_Station WHERE timestamp > 2019-07-26 x:y:00 AND timestamp < 2019-07-26 x:y+20:00, conn) 
            b = pd.read.sql("SELECT MAX(timestamp) FROM Raw_Data WHERE topic = 'lpn1' AND timestamp > 2019-07-26 x:y:00 AND timestamp < 2019-07-26 x:y+20:00, conn) 
            c = pd.read.sql("SELECT MAX(timestamp) FROM Raw_Data WHERE topic = 'RisingHF' AND timestamp > 2019-07-26 x:y:00 AND timestamp < 2019-07-26 x:y+20:00, conn) 

            list_lpn = a - b
            list_rising = a - c

等等

我们认为也许我们可以增加时间和日期，例如：

For 2019-07-26 15:00:00 to 2019-07-26 15:20:00
subtract latest data received from weather station with LPN1
subtract latest data received from weather station with RisingHF

For 2019-07-26 15:20:00 to 2019-07-26 15:40:00
subtract latest data received from weather station with LPN1
subtract latest data received from weather station with RisingHF

For 2019-07-26 15:40:00 to 2019-07-26 16:00:00
subtract latest data received from weather station with LPN1
subtract latest data received from weather station with RisingHF

import pandas as pd
from pandas.io import sql
from sqlalchemy import create_engine

list_lpn = []
list_rising = []

engine = create_engine("mysql://xxx:xxx@localhost/xxx")

conn = engine.connect()
    for x in range (24):
        for y in range (0, 20, 40):
            a = pd.read.sql("SELECT MAX(timestamp) FROM Weather_Station WHERE timestamp > 2019-07-26 x:y:00 AND timestamp < 2019-07-26 x:y+20:00, conn) 
            b = pd.read.sql("SELECT MAX(timestamp) FROM Raw_Data WHERE topic = 'lpn1' AND timestamp > 2019-07-26 x:y:00 AND timestamp < 2019-07-26 x:y+20:00, conn) 
            c = pd.read.sql("SELECT MAX(timestamp) FROM Raw_Data WHERE topic = 'RisingHF' AND timestamp > 2019-07-26 x:y:00 AND timestamp < 2019-07-26 x:y+20:00, conn) 

            list_lpn = a - b
            list_rising = a - c

表2

  id   | timestamp           | temperature1m | temperature1h | humidity1m | humidity1h |
+------+---------------------+---------------+---------------+------------+------------+
|    1 | 2019-07-26 15:00:13 |          26.9 |          28.3 |         44 |         48 |
|    2 | 2019-07-26 15:10:13 |            28 |          28.3 |         41 |         48 |
|    3 | 2019-07-26 15:20:13 |          27.8 |          28.3 |         39 |         48 |
|    4 | 2019-07-26 15:30:13 |            27 |          28.3 |         40 |         48 |
|    5 | 2019-07-26 15:40:13 |          26.8 |          28.3 |         42 |         48 |
|    6 | 2019-07-26 15:50:13 |            27 |          28.3 |         42 |         48 |
+------+---------------------+---------------+---------------+------------+------------+

---

datetime.datetime（）+datetime.timedelta（）

在一次查询中是否只需要范围

15:00到15:20

或所有范围

:00到：20

？也许在SQL中，函数只给出了几分钟的时间，然后您可以得到

minutes（timestamp）>00和minutes（timestamp）<20

。但是每个数据库可能会使用不同的语法/函数，只需要几分钟。谢谢，Furas！在我们有数据的所有日子里，我们需要每天每20分钟减去这些值！我将研究上述问题。似乎很有趣，也许你应该使用普通整数

y

和

y+20

，然后像任何其他字符串一样格式化SQL

f{x}:00{x}:{y+20}:00

或

格式（x，y，x，y+20）

（）+datetime.timedelta（）在一个查询中是否只需要范围

15:00到15:20

或所有范围

:00到：20

？也许在SQL中是一个函数，它只给出时间的分钟数，然后您可以得到

分钟（时间戳）>00和分钟（时间戳）<20

。但是每个数据库可能使用不同的语法/函数只获得分钟。谢谢，Furas！我们需要在所有有数据的日子里每天每20分钟减去一次值！我将研究上面的内容。似乎很有趣。也许你应该使用普通整数

y

和

y+20

，然后像其他stri一样格式化SQLng

f{x}:{y}:00{x}:{y+20}:00“

或

“{}:{}:00{}:{}:00”。格式（x，y，x，y+20）

BTW：如果对循环使用

，则不需要
x++
和
y++
。