Calculation of balance after each transaction - sql

Question

I have table like this:
cust_id acc_no trans_id trans_type amount
1111 1001 10 credit 2000.0
1111 1001 11 credit 1000.0
1111 1001 12 debit 1000.0
2222 1002 13 credit 2000.0
2222 1002 14 debit 1000.0
I want a Hive query or sql query for every transaction done by a customer the balance should be calculated so.
I want output as follows:
cust_id acc_no trans_id trans_type amount balance
1111.0 1001.0 10.0 credit 2000.0 2000.0
1111.0 1001.0 11.0 credit 1000.0 3000.0
1111.0 1001.0 12.0 debit 1000.0 2000.0
2222.0 1002.0 13.0 credit 2000.0 2000.0
2222.0 1002.0 14.0 debit 1000.0 1000.0
I've tried
SELECT *
FROM (SELECT cust_id,
acc_no,
trans_id,
trans_type,
amount,
CASE
WHEN Trim(trans_type) = 'credit' THEN ball =
Trim(bal) + Trim(amt)
ELSE ball = Trim(bal) - Trim(amt)
end
FROM ban) l;

Answer 1

This query will do the trick :
SELECT t1.cust_id,t1.acc_no,t1.trans_id,t1.trans_type,t1.amount,
sum(t2.amount*case when t2.trans_type = 'credit' then 1
else -1 end) as balance
FROM Table1 t1
INNER JOIN Table1 t2 ON t1.cust_id = t2.cust_id AND
t1.acc_no = t2.acc_no AND
t1.trans_id >= t2.trans_id
GROUP BY t1.cust_id,t1.acc_no,t1.trans_id,t1.trans_type,t1.amount
See SQLFIDDLE : http://www.sqlfiddle.com/#!2/3b5d8/15/0
EDIT :
SQL Fiddle
MySQL 5.5.32 Schema Setup:
CREATE TABLE Table1
(`cust_id` int, `acc_no` int, `trans_id` int,
`trans_type` varchar(6), `amount` int)
;
INSERT INTO Table1
(`cust_id`, `acc_no`, `trans_id`, `trans_type`, `amount`)
VALUES
(1111, 1001, 10, 'credit', 2000.0),
(1111, 1001, 11, 'credit', 1000.0),
(1111, 1001, 12, 'debit', 1000.0),
(2222, 1002, 13, 'credit', 2000.0),
(2222, 1002, 14, 'debit', 1000.0)
;
Query 1:
SELECT t1.cust_id,t1.acc_no,t1.trans_id,t1.trans_type,t1.amount,
sum(t2.amount*case when t2.trans_type = 'credit' then 1
else -1 end) as balance
FROM Table1 t1
INNER JOIN Table1 t2 ON t1.cust_id = t2.cust_id AND
t1.acc_no = t2.acc_no AND
t1.trans_id >= t2.trans_id
GROUP BY t1.cust_id,t1.acc_no,t1.trans_id,t1.trans_type,t1.amount
Results:
| CUST_ID | ACC_NO | TRANS_ID | TRANS_TYPE | AMOUNT | BALANCE |
|---------|--------|----------|------------|--------|---------|
| 1111 | 1001 | 10 | credit | 2000 | 2000 |
| 1111 | 1001 | 11 | credit | 1000 | 3000 |
| 1111 | 1001 | 12 | debit | 1000 | 2000 |
| 2222 | 1002 | 13 | credit | 2000 | 2000 |
| 2222 | 1002 | 14 | debit | 1000 | 1000 |

Answer 2

A simple solution is to quantify each transaction (- or +) based on trans_type and then get cumulative sum using window function .
SELECT cust_id,
acc_no,
trans_id,
trans_type,
amount,
Sum (real_amount)
OVER (ORDER BY cust_id) AS balance
FROM (SELECT cust_id,
acc_no,
trans_id,
trans_type,
amount,
( CASE trans_type
WHEN 'credit' THEN amount
WHEN 'debit' THEN amount *- 1
END ) AS real_amount
FROM test) t

Answer 3

You could do this easily through a View, calculating this directly on the table is possible but leads to performance and scalability issues (the database will slow down as the table grows). By using a View the calculation is performed as-needed; if you index the view you can keep the balances up to date without impacting the performance of the transaction table.
If you really insist on it being in the transaction table itself you could possibly use a calculated column which runs a user-defined function to determine the current balance. However this will depend largey on the specific SQL backend you're using.
Here's a basic SELECT Statement which calculates the current balance by Account:
select
acc_no,
sum(case trans_type
when 'credit' then amount
when 'debit' then amount * -1
end) as Amount
from Transactions
group by acc_no

Answer 4

You can use window function:
select cust_id,
acc_no, trans_id, trans_type, amount,
sum(pre_balance) over (partition by cust_id order by trans_id) as balance
from
(select cust_id, acc_no, trans_id, trans_type,
amount,
amount as pre_balance from test
where trans_type = 'credit'
union
select cust_id, acc_no, trans_id, trans_type,
amount, -amount as pre_balance from
test where trans_type = 'debit'
order by trans_id) as sub;

Answer 5

with current_balances as (
SELECT
id,
user_id,
SUM(amount) OVER (PARTITION BY user_id ORDER BY created ASC) as current_balance
FROM payments_transaction pt
ORDER BY created DESC
)
SELECT
pt.id,
amount,
pt.user_id,
cb.current_balance as running_balance
FROM
payments_transaction pt
INNER JOIN
current_balances cb
ON pt.id = cb.id
ORDER BY created DESC
LIMIT 10;
This will work very efficiently for big returns, and won't break on filtering or limiting. Please note that if you select only for one user or a subset of them, provide user_id filter in both current_balances cte, and the main select to omit whole table scan.

Answer 6

Table (Transaction)
-
"id" "amount" "is_credit"
1 10000 1
2 2000 0
3 5000 1
Query :
SELECT *
FROM (
SELECT id, amount, SUM(CASE When is_credit=1 Then amount Else -amount End) OVER (ORDER BY id) AS balance
FROM `Transaction`
GROUP BY id, amount
)
ORDER BY id ;
Output :
"id" "amount" "is_credit" "balance"
1 10000 1 10000
2 2000 0 8000
3 5000 1 13000