Why when adding * to query I get an error?

Question

This is probably a very very basic issue but I'm a beginner with Oracle. I'm running a simple query, which works fine and returns results, but when adding a * to the list of columns displayed, I get the below error:

ORA-00936: missing expression
00936. 00000 -  "missing expression"
*Cause:    
*Action:
Error at Line: 4 Column: 7

The query I'm running is:

select
    sql_plan_hash_value col1
    , elapsed_seconds col2
    , *
from
    (select *
    from SYS.V_$SESSION_LONGOPS
    order by elapsed_seconds desc) result_set
where rownum <= 10;

I thought that it's because I'm not giving aliases to my first two columns, so I did, but the query is still not working.

Answer 1

You can't mix raw * with other columns. You need to use the appropriate alias:

select
    sql_plan_hash_value col1
    , elapsed_seconds col2
    , result_set.* --> Like this
from
    (select *
    from SYS.V_$SESSION_LONGOPS
    order by elapsed_seconds desc) result_set
where rownum <= 10;