A logical explanation could be:- In the first query, you are telling hive which partition to overwrite, so a step which actually deletes the partition data and overwrites it with the query result, knows that which partition to delete and there is an empty result/file to move.
but for the second query, Dynamic partition step needs to deduce partition name from the query result, but as your query is not producing any row, there is no info of the partition to take action on. Regards, Tanvi Thacker On Tue, Oct 23, 2018 at 9:38 PM anci_...@yahoo.com <anci_...@yahoo.com> wrote: > Dears, > I found an interesting thing. > When inserting a NULL result into a partition which already contained > some records, there was a difference in the results between using static > partition INSERT and using dynamic partition INSERT. > See the example below: > Partition '20180101' of table A contained 100 records. > By using > we can delete the records in partition '20180101'. > But by using > there would be no change to the partition '20180101'. > In fact, if we running 'select * from A where partition_A = > '20180101'' , we will still get 100 records from it. > Expecting an explanation for it. > Thanks! > > ------------------------------ > 孙志禹 >
