Hi, Yuan As the example weihao said, +1 for be consistent with relational database.
Best --------------- Xinyu Tan On 2024/08/29 01:45:07 Yuan Tian wrote: > Hi all, > > If you are familiar with the tree model, you should know that for a device > d1, if it contains three sensors: s1, s2, s3, and its data are like: > Time | s1 | s2 | s3 | > -------|-----|-----|-----| > 1 | 1| 10|100 | > -------|-----|-----|-----| > 2 | 2| null|null | > -------|-----|-----|-----| > 3 | 3| null|null | > > > if we only query s2 and s3, select s2, s3 from root.db.d1, we will only get > one row(the first row), because for 2 and 3 row, s2 and s3 are all null, > we automatically filter out rows that are entirely null during a scan by > the storage engine. > > However, this is inconsistent with the behavior of relational databases > which will return all three rows. So in our table model, should we keep > consistent with tree model, or we follow the relational databases way? > Personally, I think that we should maintain consistency with relational > databases. > > What do you think? > > Best regards, > ---------------------- Yuan Tian >
