Hi For your first question, the answer is yes. Single star * will only represent one level node wherever in path.
"select s1, s2 from root.**.d1" will get results like root.sg.d1.s1, root.sg.group.d2.s2. ** could represent one or more levels of nodes in path. Best ---------------------------------------------------- Yukun Zhou School of Software, Tsinghua University 周钰坤 清华大学 软件学院 Xiangwei Wei <wxw19981...@gmail.com> 于2021年9月17日周五 上午9:27写道： > > Hi, > > The first question is: does single star * represent only single path node > later? > > And I support one new example, since we usually use sensor in select > clause, but it's not in 2th example. > > What about `select s1, s2 from root.**.d1" > > 周钰坤 <zykun0...@gmail.com> 于2021年9月16日周四 下午11:05写道： > > > Hi > > > > We are developing a new feature on master branch, support wildcard ** > > in IOTDB-SQL. Here's the link. > > https://github.com/apache/iotdb/pull/3918 > > Since we support * and **, and apply path pattern in SQL statement. > > Here are two type of DDL SQL to get all data under one prefixPath, and > > we want to choose one of them as default recommended statement > > presenting in UserGuide docs. > > 1. select * from <prefixPath>.**, e.g. select * from root.** > > 2. select ** from <pathPattern>, e.g. select ** from root > > Obviously, the second one is more simple than the first one. > > However, since we IoTDB have some hidden bugs in data query and > > presentation, define entities clearly in sql from clause and IoTDB > > will run more stable. That's why the second one prevails. > > > > Look forward to your suggestions. > > > > Best > > ---------------------------------------------------- > > Yukun Zhou > > School of Software, Tsinghua University > > > > 周钰坤 > > 清华大学 软件学院 > > > > > -- > Best, > Xiangwei Wei
