表结构为:user_id,Date(我习惯用时间戳)例如userid|Date(TS)A|'2014-08-1014:02:53'A|'2014-08-1214:03:25'A|'2014-08-1314:04:47'B|'2014-08-1304:04:47'...下周我有userid|Date(TS)A|'2014-08-1709:02:53'B|'2014-08-1710:04:47'B|'2014-08-1810:04:47'A|'2014-08-1910:04:22'C|'2014-08-1911:04:47'...今天我有userid|Date(TS)A|'2015-05-