Re: select count(*)

Yong wrote in message <8lsd65$rto$1_at_news.sinet.slb.com>...
>
>You probably remembered wrong. You seem to be talking about group by after
>the where clause. *That* will suppress an index scan.

Sigh .... c'mon guys, let's check our answers before we potentially mislead people. 5 minutes investigation reveals ...

select region, count(*)
from employees
where emp_id between 'P' and 'Q'
group by region

Rows Execution Plan

-------  ---------------------------------------------------
      0  SELECT STATEMENT   GOAL: CHOOSE

               OF 'EMPLOYEES'
   4508     INDEX   GOAL: ANALYZED (RANGE SCAN)
                OF 'EMPLOYEES$EMP_ID' (NON-UNIQUE)

However, I agree that the indexes are only used to *select* the rows for sorting and are not used in the sort/grouping operation itself.

(As before, example is from Oracle 8.1.5, but it applies to Oracle 7 too).

Dave.

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