Use align by device function:
select * from root.database.student align by device（any similar sql align by device）
Will print error:
Msg: 500: [INTERNAL_SERVER_ERROR] Exception occurred: "select * from root.database.student align by device". executeStatement failed. org.apache.iotdb.db.metadata.mnode.EntityMNode cannot be cast to org.apache.iotdb.db.metadata.mnode.IMeasurementMNode
Children may be path or root node. ("country" and "score" belong path, and "anhui" belongs path)if it belong to path node, they don't need to type cast and add their schema to the res. Otherwise, In 1276 lines, child not instance of IMeasurementMNode type ,so will throw ClassCastException.
The actual stored time series is shown in the figure below.