Hi Xiangdong, > if only one time series can be matched that starts with "root.sg" and ends with "s1", it is ok,otherwise throw an exception.
You are right, thanks for the illustration. > But for queries like "select s1 from root.sg.* align by device", the cases you mentioned will never happen, which is more graceful. I agree with the point you mentioned. This new feature is more suitable for align by device query, but it should be supported in raw data query too. Xiangdong Huang <[email protected]> 于2020年8月13日周四 下午5:29写道： > Hi, > > > So we have to request that *every alias input by users is matching one > time > series exactly.* > > for a query like `select s1 from root.sg.*`, if only one time series can > be matched that starts with "root.sg" and ends with "s1", it is ok, > otherwise throw an exception. > It is fine... > > But for queries like "select s1 from root.sg.* align by device", the cases > you mentioned will never happen, which is more graceful. > > So, maybe this feature is more suitable for such kind of queries. > > Best, > ----------------------------------- > Xiangdong Huang > School of Software, Tsinghua University > > 黄向东 > 清华大学 软件学院 > > > Xiangwei Wei <[email protected]> 于2020年8月13日周四 下午2:46写道： > > > Hi, > > > > I'm prepared to add a new feature in IoTDB as follows: > > > > Currently, when doing a query like *`select s1 from root.sg.d1`*, the > > result shows like: > > > > | Time | root.sg.d1.s1| > > | ... | ... | > > > > The column name *includes all prefix paths which are complex* and seem > > inflexible and inconvenient in some situations. > > > > Therefore, I think we can add a new feature by adding the alias of time > > series, which is like a relational database. For example, *`select s1 as > > d1_temperature form root.sg.d1`* > > > > The result will be like: > > > > | Time | d1_temperature | > > | ... | .... | > > > > > > However, the new feature may be *limited* in IoTDB as a time series > > database. > > Because it's not matching one time series for one suffix path exactly in > > SELECT Clause. For example, `select s1 as temperature from root.sg`. If > > two > > devices d1 and d2 exist in root.sg, then they can't both be temperature. > > We > > have to throw an exception here. > > > > So we have to request that *every alias input by users is matching one > time > > series exactly.* > > > > > > Any suggestions or questions are welcome! Thank you! > > > > > > > > -- > > Best, > > Xiangwei Wei > > > -- Best, Xiangwei Wei
