在 Oracle 中为多列计算和添加总计行

Question

I am new to sql and oracle. Below is the result of a complicated and time consuming query. I would like to calculate the sums for col2, col3 and col4. I would like to add a totals row at the end of the table.

Current Output.

id  rate rate2 col2      col3  col4
1   2,3  11    10        36     10      
1   2,4  2     229,32    36     229,32      
1   3    44    229,32    36     229,32      
1   4,5  3,4   165,2     36     90,2    
81  1,1  11    30,3      36     30,3        
81  2,3  22    10        36     10      

Desired Result. (N stands for null)

id  rate rate2 col2      col3  col4
1   2,3  11    10        36     10      
1   2,4  2     229,32    36     229,32      
1   3    44    229,32    36     229,32      
1   4,5  3,4   165,2     36     90,2    
81  1,1  11    30,3      36     30,3        
81  2,3  22    10        36     10  
N   N    N     674,14    216    599,14  

I have been doing some searching, i am able to manage this using UNION . However there is performance issue, i am running the same query calculating the totals and appending. Bottom line is i don`t want to run the same time consuming query twice. Is there any other way to manage this ?

Thanks in advance.

Answer 1

Probably the simplest method is to use union all :

with q as (
      <your query here>
     )
select q.*
from q
union all
select null, null, null, sum(col2), sum(col3), sum(col4)
from q;

Because Oracle sometimes materializes CTEs, there is not necessarily much impact on performance.

If your complicated query is an aggregation that ends in:

group by id, rate, rate2

Then grouping sets is another option:

group by grouping sets ( (id, rate, rate2), () )

Answer 2

You can use CTE and MATERIALIZE hint to fetch the desired output as following:

with cte as (SELECT /*MATERIALIZE*/ <your query after select>)
select c.*
  from cte c
union all
select null, null, null, sum(col2), sum(col3), sum(col4)
  from cte;

The undocumented MATERIALIZE hint uses global temporary table so there will be no or little performance impact.

Cheers!!