Mysql FIFO consumption - mysql

Question

I have 2 tables
article_receive , which records the the receiving via following columns;
item | title |trans_id |qty|price|current_items | current_value
ADN231 | 12" Valve |jvn2333 |24 | 175 | 24 | 4200
ADN231 | 12" Valve |jvn2388 |12 | 185 | 36 | 6420
Current Items is always total of all items
Current Value is value of all transaction combined (4200 + 2220)
For Issuance , i have article_issue with following columns;
item | title | trans_id | qty
ADN231 | 12" Valve | ISU2333 | 6
ADN231 | 12" Valve | ISU2401 | 24
My requirement is , that i want to create a consumption report, which basically calculates the exact amount of items on every issuance using FIFO method.
2nd row in article_issue has items from 2 transactions and has 2 different prices. How to calculate it in MYSQL 8.0.15 Community Version.
Currently, i am using this SQL Statement;
SELECT
article_receives.id as RCVID, article_receives.item_id, article_receives.item_title, article_receives.quantity as rcv_qty,article_receives.transaction_id, article_receives.price as rate,
article_issues.id as ISUID,article_issues.quantity as isu_qty, article_issues.quantity * article_receives.price as value
FROM article_receives
LEFT JOIN article_issues ON article_receives.item_id = article_issues.item_id
ORDER BY article_receives.item_id
/** Some Column names are changed */
This gives me data in following state;
Please help me out in creating a proper consumption report in mysql.
On side note, This is an app developed in laravel 5.8 , so eloquent is also available.
Thanks

Answer 1

Thanks to P.Salmon provided link FIFO i was able to solve the problem.
MySql Query is :
WITH
running_purchase AS
( SELECT transaction_id, created_at, quantity, item_id, price,
SUM(quantity) OVER (PARTITION BY item_id
ORDER BY created_at, transaction_id
ROWS BETWEEN UNBOUNDED PRECEDING
AND CURRENT ROW)
AS running_total
FROM article_receives
),
running_stock AS
( SELECT demand_id, created_at, quantity, item_id,
SUM(quantity) OVER (PARTITION BY item_id
ORDER BY created_at, demand_id
ROWS BETWEEN UNBOUNDED PRECEDING
AND CURRENT ROW)
AS running_total
FROM article_issues
)
SELECT
s.demand_id, p.transaction_id,p.created_at as purchase_date, p.item_id, p.price, s.created_at as issue_date,
LEAST(p.running_total, s.running_total)
- GREATEST(s.running_total - s.quantity, p.running_total - p.quantity)
AS quantity
FROM running_purchase AS p
JOIN running_stock AS s
ON p.item_id = s.item_id
AND s.running_total - s.quantity < p.running_total
AND p.running_total - p.quantity < s.running_total
WHERE s.created_at BETWEEN '2019-06-01' AND DATE_ADD('2019-06-30', INTERVAL 1 DAY)
ORDER BY
p.item_id, p.created_at, p.transaction_id ;