Oracle – How to Perform Conditional Sum in DML

dmloracle

This question was born in my mind looking at this kind of code:

select sum(value)
  into positive
  from my_table
 where value > 0;

 select sum(value)
  into negative
  from my_table
 where value < 0;

This works well for take the totals of this table.

But, my question is how I can get the sub-totals of my_table using only a statement.

expected result:

Having this data on my_table

VALUE
-----
  1.0
 -2.0
  3.0
 -4.0
  5.0
 -6.7
  8.9

I'd a DML statement who can give me this output

positive | negative
---------+---------
    17.9 |    -12.7

Is this kind of operation possible?
If yes, how can i get it?

Best Answer

SQL> r
  1  with t as (
  2      select  1.0 as x from dual
  3      union all select -2.0 as x from dual
  4      union all select  3.0 as x from dual
  5      union all select -4.0 as x from dual
  6      union all select  5.0 as x from dual
  7      union all select -6.7 as x from dual
  8      union all select  8.9 as x from dual)
  9  select sum(case when x > 0 then x else 0 end) as sum_of_positives,
 10         sum(case when x < 0 then x else 0 end) as sum_of_negatives
 11*   from t

SUM_OF_POSITIVES SUM_OF_NEGATIVES
---------------- ----------------
            17,9            -12,7
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