Yesterday, a field was added to a hive partition table in the group, and then NULL appeared when loading data, but it was clearly not NULL on hdfs. /article/details/45560591 found the answer, but when I followed the steps above, I could not find SDS, so I used another method.
Since my partition table is an external table, I delete the partition first, and then add the partition, the problem is solved.
alter table `table_name` drop partition (`partition_column_name`="partition_value");
alter table `table_name` add partition (`partition_column_name`="partition_value");