Multiply coumn with +1 or -1

Question

Multiply with -1 or +1Question:
I have two columns namely AMOUNT and IMPACT.
AMOUNT has dollar amount its of type float
IMPACT has either + or - symbol that is plus or minus symbol sadly its of type VARCHAR2.
Now i need to calculate a new column by multiplying AMOUNT with IMPACT.
So if i have
100 +
200 -
300 +
34 -
I should get
100
-200
300
-34
For every amout that has minus symbol it need to get multiplied by -1 and show a negative value in the resultant column. similarly if i have a + teh value should get multiplied by +1 and remain the same.
If i encounter something else other than - it should still be treated as 1.
I know i am not putting it in right syntax but something like this i guess
CASE
WHEN '+' THEN 1
WHEN '-' THEN -1
ELSE 0

Answer 1

Try something like:
SQL> -- generating your sample data:
SQL> with t as (
  2  select 100 amount, '+' impact from dual union
  3  select 200, '-' from dual union
  4  select 300, '+' from dual union
  5  select 34, '-'  from dual union
  6  select 3400, '¿?'  from dual
  7  )
  8  --
  9  -- actual query:
10  --
11  select amount
12  ,      impact
13  ,      to_number( case
14                      when impact = '+' then amount*1
15                      when impact = '-' then amount*-1
16                      else amount*1
17                    end
18                  ) new_amount
19  from   t;
    AMOUNT IMP NEW_AMOUNT
        34 -          -34
       100 +          100
       200 -         -200
       300 +          300
      3400 ¿?        3400