SQL Queries - CAST Central Base - Queries on Objects - How to count the number of added deleted and modified objects betweeen two snapshots

select count(doi1.OBJECT_ID) as "Deleted",    
       count(doi2.OBJECT_ID) as "Added",     
       count(doi1.OBJECT_ID + doi2.OBJECT_ID) as "Modified"
  from (select doi1.OBJECT_ID,            
               doi1.OBJECT_CHECKSUM       
         from DSS_OBJECT_INFO doi1
        where doi1.SNAPSHOT_ID = [1st snapshot ID]
        ) doi1
  full join
       (select doi2.OBJECT_ID,             
               doi2.OBJECT_CHECKSUM        
          from DSS_OBJECT_INFO doi2
         where doi2.SNAPSHOT_ID = [2nd snapshot ID]
        ) doi2
    on doi1.OBJECT_ID = doi2.OBJECT_ID
where doi1.OBJECT_ID is null
   or doi2.OBJECT_ID is null
   or doi1.OBJECT_CHECKUM !=
doi2.OBJECT_CHECKSUM;