当时序不存在的时候能否直接返回空

[Haze-Lan]

IoTDB> select variable,number,save,value from root.product.1_data.57 where time >=1664146800000 and time <=1664153923031 and variable in ( 'Location') order by time asc Msg: 411: Error occurred in query process: Unknown time series root.product.1_data.57.variable in where clause

因为设备未报数据过来所以 表内是没有数据的，如果要过滤某个值就会报错，这里能不能处理成跟time一样 没有值就返回为空

[HTHou]

@JackieTien97

[github-actions[bot]]

Hi, this is your first issue in IoTDB project. Thanks for your report. Welcome to join the community!

[jixuan1989]

IMO, it is different between "no data" and "no schema".. Users may need to do some other action when they meet the latter case.

[qiaojialin]

Thanks for reporting, we will optimize this https://issues.apache.org/jira/browse/IOTDB-4576

[Wei-hao-Li]

Has implemented in this PR.