Count(1) vs count(*)

Hey once again the same old question:
Whats the difference between count(1) vs count(*)
I have read this through many forums and looks like there's no difference and more specifically with latest version of database Optimizer is smart enough to translate b/w * and 1.
My understanding so far says in Indexed table if you do select 1 from <<table>> it should not be even routed to Table and index fast scan would give back the results vs select * which will get routed to table to check null-ability on all columns.
Am i missing something.
comments welcome.
Thanks!

Hi, Rohit,
rohitgoswami wrote:
No, it sounds like you understand.
so wouldn't count(1) use index vs count(*) use table?.No. Why would the optimezer do anything different in those two cases? Neither one depends on what's in any row of the table, or what's in any index entry.
I will make discussion more generic without even putting oracle in picture. Lets say we have a book that has 1000 pages and it has a index. essentially we are saying is below:
1.) going to first page of the book and reading the index and getting the page number of where chapter endsIn general, the index of a book says nothing about how many pages are in each chapter. Did you mean "table of contents" rather than "index"?
is same as
2.) going through all pages of the book and reading the page number to get there are 1000 pages.I don't see the analogy. Neither 1) nor 2) above seems to have anything in common with using an index to count the number of rows in a table.

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Basic questions are not allowed. Please put some effort from your side, before turning to the forums for help. Use the existing tools (F1 Help, ABAPDOCU, Google, SAP Help, etc) first to resolve your issue. Thread locked
Edited by: kishan P on Aug 24, 2010 9:43 AM

Hello,
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Basic questions are not allowed. Please put some effort from your side, before turning to the forums for help. Use the existing tools (F1 Help, ABAPDOCU, Google, SAP Help, etc) first to resolve your issue. Thread locked
Edited by: kishan P on Aug 24, 2010 9:43 AM

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