what is the main diffrence between aggregation and rollup aggregation?

[bvk.cognoise]

Hi,

can you please give me the main difference between aggregation and rollup aggregation?please dont give definition.can you please explain it with best example clearly?


thanks
bvk

[technomorph]

Detail Rows - without auto group and summarised applied:

Month	Product	Value
1	A	100
1	A	100
1	B	50
2	C	200
3	B	50
3	B	50
4	D	75

Detail Rows  - with auto group and summarised applied plus the Total Aggregate function applied to the Value column:

Month	Product	Value
1	A	200
1	B	50
2	C	200
3	B	100
4	D	75

Detail Rows  - with auto group and summarised applied plus the Maximum Aggregate function applied to the Value column:

Month	Product	Value
1	A	200
1	B	200
2	C	200
3	B	200
4	D	200

Detail Rows  - with auto group and summarised applied, plus the Total Aggregate function applied to the Value column, plus the Total Rollup Aggregate function applied to the Value column (assuming you have added an overall footer row):

Month	Product	Value
1	A	200
1	B	50
2	C	200
3	B	100
4	D	75
Total		625

[blom0344]

Hi,

can you please give me the main difference between aggregation and rollup aggregation?please dont give definition.can you please explain it with best example clearly?


thanks
bvk

aggregation is explicit; it leads to aggr. functions within the SQL generated. Rollup is implicit; the cognos server perform a totalization to the next highest level or a single value for the report / grouped value / section. The result of rollup's cannot be traced directly to the execution on the database, but is the result of a server action. Same goes for 'running' values.
SQL can only generate such values through complex nested non-equi joins. You will find them there , it is the Cognos server that produces them..

[ricky_ru]

Glad to know it. Thanks you guys.