Find the balance amount (sum(credit) – sum(debit)) from the following table?

Ans: find out the balance amount of account no: 1

select  a.SumCr as Credit ,
        b.SumDr as Debit ,
        a.SumCr - b.SumDr as Balance
from    ( select    sum(A_Amount) as SumCr
          from      tblAccount
          where     A_ID = 1
                    and A_Type = 'Cr'
        ) a ,
        ( select    sum(A_Amount) as SumDr
          from      tblAccount
          where     A_ID = 1
                    and A_Type = 'Dr'
        ) b

Ans: find out the balance amount for all the account numbers in the table:

select  a.A_ID as ID ,
        a.SumCr as Credit ,
        b.SumDr as Debit ,
        a.SumCr - b.SumDr as Balance
from    ( select    A_ID ,
                    sum(A_Amount) as SumCr
          from      tblAccount
          where     A_Type = 'Cr'
          group by  A_ID
        ) a
        inner join ( select A_ID ,
                            sum(A_Amount) as SumDr
                     from   tblAccount
                     where  A_Type = 'Dr'
                     group by A_ID
                   ) b on a.A_ID = b.A_ID