datetime.datetime 和datetime.date 无法比较 can't compare datetime.datetime to datetime.date

mysql 读出来的date类型的数据，在python中是datetime.date，但是通过

datetime.datetime.strptime(hgml+'-01','%Y-%m-%d')得到的类型是datetime.datetime类型，两者无法比较。

解决方法：将datetime.datetime转成datetime.date即可比较

datetime.datetime.date(datetime.datetime.strptime(hgml+'-01','%Y-%m-%d'))  #参数是datetime.datetime

另，python如何求，月初和月末

hgml='2020-01'

month_first_day = datetime.datetime.date(datetime.datetime.strptime(hgml+'-01','%Y-%m-%d'))
month_last_day = datetime.date(month_first_day.year, month_first_day.month, calendar.monthrange(month_first_day.year, month_first_day.month)[1])