Hi Tom,

I am a newbie in oracle and few of my friends are arguing that count(rowid) is faster than count(1) or count(*)

But when i ran the below queries in 2 different sessions

select count(1) from table
and select count(rowid) from table. Both are taking almost the same time

I read one of your posts where you mentioned the below point

"count(rowid) askes for the count of non-null rowids. why bother to check the non-nullness if all you want is a count."

FYR here is the older post which i am reffering
https://asktom.oracle.com/pls/asktom/f?p=100:11:::::P11_QUESTION_ID:1156151916789

I am sure you are right always but how come rowid be null as it is the physical address. Can you please explain me this, please correct my understanding if i was wrong

Thanks and Regards,
Rajendra Kalepu.

create table t1 as
  select rownum x from dual connect by level <= 2;

create table t2 as
  select * from t1 where rownum <= 1;

select count(*), count(t1.rowid) t1rid, count(t2.rowid) t2rid
from   t1 left join t2 
on     t1.x = t2.x;

  COUNT(*)      T1RID      T2RID
---------- ---------- ----------
         2          2          1