Can I MERGE INTO ... INSERT with a column list in Hive?
Every example I've seen includes all of the columns.  I also found this note about updates (though nothing specific to insert):


  Note that you cannot update only a part of a complex structure field. For example, suppose you have a structure stored as one field in a Hive table:
  {"name":"Johnson","surname":"Fall","age":23,"gender":"MALE"}
  You cannot update only the age field in the structure. You can only replace all values of the structure with new ones.


From: https://mapr.com/docs/61/Hive/MERGE_Statement_with_MapR-DB-JSON-tables.html