Calculate running clossing stock and profit by average purchase price in mysql - mysql

Question

I need to insert new quantities to the stock table (a1) from source table (a2) and when on insertion closing stock, profit should be calculated. My stock (a1) table as
CREATE TABLE IF NOT EXISTS `a1` (
`id` int NOT NULL AUTO_INCREMENT,
`trs_date` date NOT NULL,
`product_id` int NOT NULL,
`qty_in` decimal(5,2) NOT NULL,
`price_in` decimal(5,2) NOT NULL,
`amount_in` decimal(5,2) NOT NULL,
`qty_out` decimal(5,2) NOT NULL,
`price_out` decimal(5,2) NOT NULL,
`amount_out` decimal(5,2) NOT NULL,
`qty_bal` decimal(5,2) NOT NULL,
`price_bal` decimal(5,2) NOT NULL,
`amount_bal` decimal(5,2) NOT NULL,
`profit` decimal(5,2) NOT NULL DEFAULT '0.00',
PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=6 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;
INSERT INTO `a1` (`id`, `trs_date`, `product_id`, `qty_in`, `price_in`, `amount_in`, `qty_out`, `price_out`, `amount_out`, `qty_bal`, `price_bal`, `amount_bal`, `profit`) VALUES
(1, '2022-01-01', 1, '10.00', '2.00', '20.00', '0.00', '0.00', '0.00', '10.00', '2.00', '20.00', '0.00'),
(2, '2022-01-01', 2, '20.00', '10.00', '200.00', '0.00', '0.00', '0.00', '20.00', '10.00', '200.00', '0.00'),
(3, '2022-01-02', 1, '5.00', '3.00', '15.00', '0.00', '0.00', '0.00', '15.00', '2.33', '35.00', '0.00'),
(4, '2022-01-02', 2, '0.00', '0.00', '0.00', '5.00', '8.00', '40.00', '15.00', '10.00', '150.00', '-10.00'),
(5, '2022-01-03', 1, '0.00', '0.00', '0.00', '8.00', '9.00', '72.00', '7.00', '2.33', '16.31', '53.36');
and Source Table (a2) as
CREATE TABLE IF NOT EXISTS `a2` (
`id` int NOT NULL AUTO_INCREMENT,
`trs_date` date NOT NULL,
`product_id` int NOT NULL,
`qty_in` decimal(5,2) NOT NULL,
`price_in` decimal(5,2) NOT NULL,
`amount_in` decimal(5,2) NOT NULL,
`qty_out` decimal(5,2) NOT NULL,
`price_out` decimal(5,2) NOT NULL,
`amount_out` decimal(5,2) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=7 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;
INSERT INTO `a2` (`id`, `trs_date`, `product_id`, `qty_in`, `price_in`, `amount_in`, `qty_out`, `price_out`, `amount_out`) VALUES
(4, '2022-01-03', 1, '50.00', '4.00', '200.00', '0.00', '0.00', '0.00'),
(5, '2022-01-04', 2, '60.00', '8.00', '480.00', '0.00', '0.00', '0.00'),
(6, '2022-01-05', 1, '0.00', '0.00', '0.00', '10.00', '15.00', '150.00');
Now I need to insert data from a2 to a1 and closing quantity,rate,amount and profit should be calculated.
Closing Quantity = Previous Quantity + Quantity In - Quantity Out
Closing Price (Average Purchase Price)= (Previous Amount Balance + Amount In) / (Previous
Quantity + Quantity In)
Closing Amount = Closing Quantity * Closing Price
Profit = Quantity Out * (Price Out - Closing Price)
My query as follows
insert into a1 (trs_date, product_id, qty_in,price_in,amount_in,qty_out,price_out,amount_out,
qty_bal,price_bal,amount_bal,profit)
with cte_balance as (
select
*,
row_number() over (partition by product_id order by trs_date desc, id desc) as rn
from a1
),
cte_receive as (
select
id, trs_date, product_id, qty_in,price_in,amount_in,qty_out,price_out,amount_out,
qty_bal,price_bal,amount_bal,profit, rn as skip_flag
from cte_balance where rn = 1
union all
select
id, trs_date, product_id, qty_in,price_in,amount_in,qty_out,price_out,amount_out,
0 AS qty_bal,0 AS price_bal,0 AS amount_bal,0 AS profit,0 as skip_flag
from a2
),
cte_new_balance as (
select
id, trs_date, product_id, qty_in,price_in,amount_in,qty_out,price_out,amount_out,
(LAG(qty_bal) over (partition by product_id order by skip_flag DESC, trs_date, id)+qty_in-qty_out) as qty_bal,
0 as amt_bal,
(LAG (amount_bal) over (partition by product_id order by skip_flag DESC, trs_date, id)+ amount_bal)/
(LAG (qty_bal) over (partition by product_id order by skip_flag DESC, trs_date, id)+ qty_bal) as rate_bal,
0 AS new_profit,
skip_flag
from cte_receive
)
select
trs_date, product_id, qty_in,price_in,amount_in,qty_out,price_out,amount_out,
qty_bal as qty_bal,rate_bal AS price_bal,qty_bal*rate_bal AS amount_bal,new_profit AS profit
from cte_new_balance
where skip_flag = 0;
Where cte_balance is to take latest data of each product from table a1, and cte_receive combines the latest data with new data from a2. The query giving unexpected result, my expected result, Table a1 should be as

Answer 1

Get last qty_bal per product (Note to order by trs_date desc, id desc in case more than one row in a day)
Union with receives in a2 (added skip_flag)
Calculate new qty_bal per row (To order by trs_date, id to get data in proper order)
insert into a1 (trs_date, product_id, qty_in, qty_out, qty_bal)
with cte_balance as (
select id, trs_date, product_id, qty_in, qty_out, qty_bal,
row_number() over (partition by product_id order by trs_date desc, id desc) as rn
from a1),
cte_receive as (
select id, trs_date, product_id, 0 as qty_in, 0 as qty_out, qty_bal, rn as skip_flag from cte_balance where rn = 1
union all
select id, trs_date, product_id, qty_in, qty_out, qty_in-qty_out, 0 from a2),
cte_new_balance as (
select id, trs_date, product_id, qty_in, qty_out, qty_bal,
sum(qty_bal) over (partition by product_id order by trs_date, id) as new_bal,
skip_flag
from cte_receive)
select trs_date, product_id, qty_in, qty_out, new_bal as qty_bal
from cte_new_balance
where skip_flag = 0;