GROUP BY

Hello Oracle gurus,

My question is as follows:

I have a huge table with 10,000,000 records. And we are frequently running a query with a GROUP BY statement. Would an index on the grouped columns improve the performance? It seems to me that there is not really any need for an index since the best algorithm for such a query would have to do a full-table scan and increment the appropriate counters.

the SQL statement is :

select mar_status, apr_status , count(*) from master_table
group by mar_status, apr_status;

If only subset of the records are needed by specifying a where clause as shown in the SQL statement below and one of the filters is the grouped column, would that make a difference?

select mar_status, apr_status , count(*) from master_table
where mar_status in ('1','2')
group by mar_status, apr_status;

Thanks and have a crash free day...

Tansel Received on Wed Aug 20 1997 - 00:00:00 CDT