I am new to SQL. I have one banking project, in the in one table have values like this.
Debit 1000........... so on
You can also use decode instead of case.
To print the signed value as string
select decode(type,'Debit','-','+')||amount as value from tab;
To keep the value as number but signed
select decode(type,'Debit',-1*amount,amount) as value from tab;