Hi, > My question is, is the data point at 1d calculated twice?
The answer is NO. If it calculated twice, it's a bug. > it loses the ability to define the start point of the timestamp for splitting the time window. The new group by statement is like this: select count(*) from root where time >= 1 and time <= 100 group by ([0, 100], 20ms, 20ms) The 0 in [0, 100] is used as the start point. This statement should satisfy most scenarios. Thanks, Jialin Qiao xiangdong Huang (Jira) <[email protected]> 于2019年12月10日周二 下午4:50写道： > xiangdong Huang created IOTDB-358: > ------------------------------------- > > Summary: Questions about the `group by` down-samplying clause > Key: IOTDB-358 > URL: https://issues.apache.org/jira/browse/IOTDB-358 > Project: Apache IoTDB > Issue Type: Bug > Affects Versions: 0.9.0 > Reporter: xiangdong Huang > > > When reading issue #331, I read the `group by` document again and find > some confusing contents: > > V0.9: > > [http://iotdb.apache.org/#/Documents/0.9.0/chap5/sec2] > # (minor), typo, Fig 5.2 rather than Fig 3.2 > # The first parameter of the GROUP BY statement above is the time > interval for dividing the time axis. Taking this parameter (1d) as time > interval and the default origin as the dividing origin, the time axis is > divided into several continuous intervals, which are [0,1d], [1d, 2d], [2d, > 3d], etc. > > My question is, is the data point at 1d calculated twice? > > > > V0.10: > [http://iotdb.apache.org/#/Documents/progress/chap5/sec2] > > the syntax is quite different with v0.9.0. I originally thought it was an > improvement comparing with 0.9, but when I read the document, I find it > loses the ability to define the start point of the timestamp for splitting > the time window. > > Can someone tell me why to design like this? > > > > > > > > -- > This message was sent by Atlassian Jira > (v8.3.4#803005) > -- ————————————————— Jialin Qiao School of Software, Tsinghua University 乔嘉林 清华大学 软件学院
