aggregate and roll up aggregate function in list report

[Shailaja0520]

Can anyone explain the aggregate function and roll up aggreagte function property  with some scenario.
thanks in advance.

[blom0344]

The aggregate indicates whether Cognos is going to use sum/count/max/min in the SQL that it builds against the database.

The rollup aggregate defines how the Cognos server 'rolls up' measures when the reporting grain is higher than the grain of the SQL output:

Example:

If you fetch sales by year and month in the query and totalize it then Cognos will add 'sum' against the sales.

If you report on this set, but leave out the month level, then the rollup will tell the server (if rollup is total) to totalize the sales to year-level and display this in the report.