Missing Numbers (Between two numbers)

[aspdba]

SQL> create table test as select rownum rno from user_objects where rownum<10;

Table created.

Elapsed: 00:00:00.47
SQL> select * From test;

       RNO                                                                                                                    
==========                                                                                                                    
         1                                                                                                                    
         2                                                                                                                    
         3                                                                                                                    
         4                                                                                                                    
         5                                                                                                                    
         6                                                                                                                    
         7                                                                                                                    
         8                                                                                                                    
         9                                                                                                                    

9 rows selected.

Elapsed: 00:00:00.78
SQL> delete from test where rno=6;

1 row deleted.

Elapsed: 00:00:00.40
SQL> commit;

Commit complete.Elapsed: 00:00:00.25
SQL>  select rno+1 from test a
  2   where not exists (select null from test b
  3   where b.rno=a.rno+1)
  4  /

     RNO+1                                                                                                                    
==========                                                                                                                    
         6                                                                                                                    
        10                                                                                                                    

Elapsed: 00:00:00.19 

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