需要执行简单的时间转换,比如天到秒,小时到分钟等的转换. 为了执行不同时间单位的转换和计算,请使用datetime 模块.比如,为了表示一个时间段,可以创建一个timedelta 实例,就像下面这样: >>> from datetime import timedelta >>> a = timedelta(days=2, hours=6) >>> b = timedelta(hours=4.5) >>> c = a + b >&
1.inner join ,left join 与 right join (from 百度知道) 例表aaid adate1 a12 a23 a3表bbid bdate1 b12 b24 b4 (1)两个表a,b相连接,要取出id相同的字段 select * from a inner join b on a.aid = b.bid 此时的取出的是:1 a1 b12 a2 b2 (2)left join 指:select * from a left jo
/* 时间转换start */ public static void main(String args[]) { Date nowTime = new Date(); System.out.println(nowTime); SimpleDateFormat time = new SimpleDateFormat("yyyy/M/d"); BeanDayTraffic bd = new BeanDayTraffic(); System.out.println(time.format(n