Question

I need to select data at different granular level (in Oracle). I have a table with data as:

c1  c2  c3  c4
a   a1  10  5
a   a2  10  5
b   b1  10  5
b   b2  10  5

I need to write a query that would return data as:

c1  c2  c3
a   20  10   --aggregated data
a1  10  5    --lowest granular level data
a2  10  5    --lowest granular level data
b   20  10
b1  10  5    -- data of b1, b2 should follow the data of b; likewise a1, a2 should follow data of a
b2  10  5

I find this quite unusual because I need to select data at both lowest granular level and an aggregated level. How can I do this?

Answer 1

You may start from this:

SELECT C1, C2, sum(c3), sum(c4), grouping_id(c1, c2)
FROM table_name
group by rollup(c1,c2)

To get only your groups you need

SELECT C1, C2, sum(c3), sum(c4), grouping_id(c1, c2)
FROM table_name
group by GROUPING SETS ( (c1, c2), c1)

see here another examples and explanations.