我正在使用python连接到sqlserver数据库并执行几个“select”类型的查询，这些查询包含以特定方式编写的日期范围。所有这些查询都有相同的日期范围，所以我不想硬编码它，而是希望它作为一个字符串，只在需要时在一个地方更改它。到目前为止，我发现我可以使用datetime模块和以下逻辑将日期转换为字符串：

from datetime import datetime
start_date = datetime(2020,1,1).strftime("%Y-%m-%d")
end_date = datetime(2020,1,31).strftime("%Y-%m-%d")

查询示例：

select * from where xxx='yyy' and time between start_date and end_date

我该怎么做？
编辑我的代码：

import pyodbc
import sqlalchemy
from sqlalchemy import create_engine
from datetime import datetime

start_date = datetime(2020,1,1).strftime("%Y-%m-%d")
end_date = datetime(2020,1,31).strftime("%Y-%m-%d")

engine = create_engine("mssql+pyodbc://user:pwd@server/monitor2?driver=SQL+Server+Native+Client+11.0")

sql_query = """ SELECT TOP 1000 
      [mtime]
      ,[avgvalue]
  FROM [monitor2].[dbo].[t_statistics_agg]
  where place = 'Europe' and mtime between 'start_date' and 'end_date'
  order by [mtime] asc;"""

df = pd.read_sql(sql_query, engine)
print(df)