问题
Please someone help me to make a MySql query for running balance correction.
Actually We have very much dirty data that came from other application. Sometimes we got negative balance for normal running balance calculation.
From the question before I got an answer but I want credit transaction only calculating first if the normal balance calculation is negative so if the balance does not negative then the order of debit and credit within the same date should not change
Here is the table example:
trx_no trx_date Opening debit credit
1 2019-10-01 200 0 100
2 2019-10-02 200 0 100
3 2019-10-03 200 100 0
4 2019-10-03 200 400 0
5 2019-10-03 200 0 200
6 2019-10-04 200 0 100
7 2019-10-05 200 100 0
8 2019-10-05 200 0 400
For normal balance calculation we got negative balance:
trx_no trx_date Opening debit credit balance
1 2019-10-01 200 0 100 300
2 2019-10-02 200 0 100 400
3 2019-10-03 200 100 0 300
4 2019-10-03 200 400 0 -100 <- negative balance
5 2019-10-03 200 0 200 100
6 2019-10-04 200 0 100 200
7 2019-10-05 200 100 0 100
8 2019-10-05 200 0 400 500
Here is the query I got from @forpas (many thanks) :
SELECT
t1.trx_no,
t1.trx_date,
t1.Opening,
t1.debit,
t1.credit,
t1.Opening + (
SELECT SUM(t2.credit - t2.debit)
FROM MyTable t2
WHERE
concat(t2.trx_date, t2.debit > t2.credit, lpad(t2.trx_no, 10, '0')) <=
concat(t1.trx_date, t1.debit > t1.credit, lpad(t1.trx_no, 10, '0'))
) AS balance
FROM MyTable t1
ORDER BY concat(t1.trx_date, t1.debit > t1.credit, lpad(t1.trx_no, 10, '0'))
Below is the result for above query, no negative balance but trx_no 8 ordered before trx_no 7:
trx_no trx_date Opening debit credit balance
1 2019-10-01 200 0 100 300
2 2019-10-02 200 0 100 400
5 2019-10-03 200 0 200 600
3 2019-10-03 200 100 0 500
4 2019-10-03 200 400 0 100
6 2019-10-04 200 0 100 200
8 2019-10-05 200 0 400 600
7 2019-10-05 200 100 0 500
The result what we need is below. Credit transaction only calculating first if the balance is negative. So if the balance not negative the order should not changed:
trx_no trx_date Opening debit credit balance
1 2019-10-01 200 0 100 300
2 2019-10-02 200 0 100 400
5 2019-10-03 200 0 200 600
3 2019-10-03 200 100 0 500
4 2019-10-03 200 400 0 100
6 2019-10-04 200 0 100 200
7 2019-10-05 200 100 0 100
8 2019-10-05 200 0 400 500
Here is the DEMO
回答1:
I don't think this can be done using set based code since you need read ahead and read back. Something procedural could work. Using a cursor and a temporary table I can pretty much accomplish that (you need to add stuff to ensure that cumulative balance does not go negative). From what you say the first transaction can never take the balance negative but I would check for that. Note well the takes from the credit pool may come from a later date than the debit the take is compensating for - since the balance can never go negative then that should not be a problem (sic). And of course I would not expect the performance to be great.
DROP TABLE IF EXISTS T;
create table t
(trx_no int, trx_date date, Opening int,debit int, credit int);
insert into t values
(1 , '2019-10-01' , 200 , 0 , 100),
(2 , '2019-10-02' , 200 , 0 , 100),
(3 , '2019-10-03' , 200 , 100 , 0 ),
(4 , '2019-10-03' , 200 , 400 , 0 ),
(5 , '2019-10-03' , 200 , 0 , 200),
(6 , '2019-10-04' , 200 , 0 , 100),
(7 , '2019-10-05' , 200 , 100 , 0 ),
(8 , '2019-10-05' , 200 , 0 , 400);
DROP TABLE IF EXISTS stmT;
create table stmt
(trx_no int, trx_date date, Opening int,debit int, credit int, cumbal int);
drop procedure if exists p;
delimiter $$
create procedure p()
begin
declare v_trx_no int;
declare v_dt date;
declare v_debit int;
declare v_credit int;
declare h_trx_no int;
declare h_dt date;
declare h_credit int;
declare opbal int;
declare rbal int;
declare done int default 0;
declare cur cursor for select trx_no,trx_date,debit,credit from t order by trx_date,trx_no;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
select opening into opbal from t order by trx_no limit 1;
set rbal = opbal;
drop table if exists creditpool;
create temporary table if not exists creditpool as select trx_no,trx_date,credit,0 as used from t where credit > 0;
#select * from creditpool;
open cur;
cursorloop:loop
fetch cur into v_trx_no,v_dt,v_debit,v_credit;
if done = true then
leave cursorloop;
end if;
if v_credit > 0 and exists (select 1 from creditpool where trx_no = v_trx_no and used = 0) then
if v_credit > 0 then
insert into stmt values (v_trx_no,v_dt,opbal,v_debit,v_credit, rbal + v_credit);
set rbal = rbal + v_credit;
update creditpool set used = 1 where trx_no = v_trx_no;
end if;
end if;
if v_debit > 0 and v_debit <= rbal then
insert into stmt values (v_trx_no,v_dt,opbal,v_debit,v_credit, rbal - v_debit);
set rbal = rbal - v_debit;
elseif v_debit > 0 and v_debit > rbal then
poolloop: loop
select trx_no,trx_date,credit
into h_trx_no,h_dt,h_credit
from creditpool
where used = 0
order by trx_date,trx_no limit 1;
insert into stmt values (h_trx_no,h_dt,opbal,0,h_credit, rbal + h_credit);
set rbal = rbal + h_credit;
update creditpool set used = 1 where trx_no = h_trx_no;
if v_debit <= rbal then
insert into stmt values (v_trx_no,v_dt,opbal,v_debit,v_credit, rbal - v_debit);
set rbal = rbal - v_debit;
leave poolloop;
end if;
end loop poolloop;
end if;
end loop cursorloop;
close cur;
end $$
delimiter ;
truncate stmt;
call p();
select * from stmt;
+--------+------------+---------+-------+--------+--------+
| trx_no | trx_date | Opening | debit | credit | cumbal |
+--------+------------+---------+-------+--------+--------+
| 1 | 2019-10-01 | 200 | 0 | 100 | 300 |
| 2 | 2019-10-02 | 200 | 0 | 100 | 400 |
| 3 | 2019-10-03 | 200 | 100 | 0 | 300 |
| 5 | 2019-10-03 | 200 | 0 | 200 | 500 |
| 4 | 2019-10-03 | 200 | 400 | 0 | 100 |
| 6 | 2019-10-04 | 200 | 0 | 100 | 200 |
| 7 | 2019-10-05 | 200 | 100 | 0 | 100 |
| 8 | 2019-10-05 | 200 | 0 | 400 | 500 |
+--------+------------+---------+-------+--------+--------+
8 rows in set (0.00 sec)
Note the outcome is slightly different to your desired result because a take only occurs when required.
来源：https://stackoverflow.com/questions/58454140/mysql-query-for-running-balance-correction