datetime时间值比较

    数据库中存放的时间值需要与当前时间相互比较，查看了相关文档，有以下的实现：

from datetime import datetime

time_str1 = '2017-03-09 13:55:57'
time_str2 = '2017-03-09 13:57:30'

time_obj1 = datetime.strptime(time_str1, "%Y-%m-%d %H:%M:%S")
time_obj2 = datetime.strptime(time_str2, "%Y-%m-%d %H:%M:%S")
time_obj3 = datetime.now()

print time_obj3 - time_obj1
print (time_obj3 - time_obj1).seconds/60