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 >
