Hi Suren,
1. First, when you select data from a partitioned table, SAP HANA knows which partition owns which data. For example, if your table is partitioned by range, Jan on part. 1, Feb on part. 2 and Mar on part. 3. You just want to select data in Jan, then you just run your select SQL statement, SAP HANA will do the pruning automatically. You do not need to select which partition to do the job. It is transparent to you. In addition, I don't think it make sense you want to select data from a certain partition, if the table is partitioned by hash or round-robin. The result is meaningless.
2. Yes, this statement will create partitions and move data to corresponding partitions. But it will take some time if your table is huge.
Best regards,
Wenjun