How Do I collapse rows on null values in t-sql?

Question

I\'m in a weird situation with my query. My objective is to display the total deposits and withdrawals from multiple transactions for each person and display them. I am getting

Answer 1

Solution using Subquery

select t.lastname, t.firsname,sum(t.Withdrawal) Withdrawal ,sum(t.Deposit) Deposit,t.description from(
select lastname, firsname,
       isnull(case when upper(category) = 'W' then abs(principal) end,0) as Withdrawal,
       isnull(case when upper(category) = 'D' then abs(principal) end,0) as Deposit,
description
from table1 join
     table2
     on table2.id = table1.id join
     table3
     on table3.c = table2.c
where description = 'string'
)t group by t.lastname, t.firstname, t.description, t.category