find total of positive and negative numbers separately inline, using only select and case statement

Question

I have a question. If I am given a table with positive and negative numbers and I want to find total of all positives and total of all negatives separately and display it in one line. I was able to come up with one solution (below). I wanted to check if it is possible to have a better solution using Select and CASE statement

id  amount
1   100
2   -10
3   50
4   -80
5   20
6   -20

positive negative
170         -110

My Solution:

    create table #temp (id int, amount int)
insert into #temp values (1, 100)
insert into #temp values (2, -10)
insert into #temp values (3, 50)
insert into #temp values (4, -80)
insert into #temp values (5, 20)
insert into #temp values (6, -20)

with positive as 
(select sum(amount) as posNum from temp where amount > 0)
, negative as 
(select sum(amount) as negNum from temp where amount < 0)
select *, (select * from negative) from positive 

Answer 1

Use conditional aggregation: https://dbfiddle.uk/?rdbms=sqlserver_2017&fiddle=e2fa9cc6aee27cc501c9cda98bc2cf2d

SELECT
    SUM(CASE WHEN amount > 0 THEN amount END) AS positive,
    SUM(CASE WHEN amount < 0 THEN amount END) AS negative
FROM #temp;

Output:

positive    negetive
170         -110

Answer 2

You can also use sign() to determine it is positive or negative number

select  sum(case when sign(amount) = 1 then amount end),
        sum(case when sign(amount) = -1 then amount end)
from    #temp

Answer 3

This will work:

1) For SQL Server

SELECT
    SUM(IIF(amount > 0, amount, 0)) positive,
    SUM(IIF(amount < 0, amount, 0)) negative
FROM TABLENAME;

2) For SQL Server and MySQL

SELECT
    SUM(CASE WHEN amount > 0 THEN amount END) positive,
    SUM(CASE WHEN amount < 0 THEN amount END) negative
FROM TABLENAME;