Stock Available Performance Mysql - mysql

Question

I am trying to fetch the value of available stock in MYSQL but when the number of rows gets more than 35000 request is failing with no response. I use subqueries to fetch the value of the available stock.
Here is my code:
SELECT
p.`product-id` AS id,
p.`product-id` AS product_id,
ped.purchase_entry_id AS purchase_id,
p.`product-name` AS name,
m.name AS manufacturer,
p.`product-type` AS product_type,
ped.id AS batch_no,
ped.internal_sales_rate AS barcode,
c.name as category,
ped.size AS size,
IFNULL(ped.sales_rate,0) AS sales_rate,
IFNULL(ped.purchase_rate,0) AS purchase_rate,
IFNULL(SUM(ped.units),0) AS units_purchased,
(select IFNULL(SUM(sed.qty),0) FROM sales_entry_details sed WHERE (sed.batch_no = ped.id)) AS units_sold,
(select IFNULL(SUM(sr.qty),0) FROM sales_return_item sr WHERE (sr.batch_no = ped.id)) AS retured,
(select IFNULL(SUM(pri.qty),0) FROM purchase_return_items pri WHERE (pri.batch_no = ped.id)) AS purchase_return,
(select IFNULL(SUM(ast.qty),0) FROM adjustment_stock ast WHERE (ast.batch_no = ped.id)) AS adjustment,
(select IFNULL(SUM(ast2.batch_no),0) FROM adjustment_stock ast2 WHERE (ast2.batch_no = ped.id)) AS isChecked
FROM purchase_entry_details ped
LEFT JOIN products p on p.`product-id` = ped.product_id
LEFT JOIN category c ON c.id = p.`product-type`
LEFT JOIN manufacturer m ON m.id = p.manufacturer
GROUP BY ped.id;
Is there any better option to fetch the value of stock available in SQL??

Answer 1

The query looks fine. As there is no limiting criteria (no WHERE clause), you'll read the whole table sequentially.
You'd want indexes on batch_no in the involved tables of course. But I guess these are foreign keys to some batch table, so the indexes should already exist.
The only thing that I notice is that you select from adjustment_stock twice. You can avoid this by moving the subqueries to your FROM clause:
SELECT
p.`product-id` AS id,
p.`product-id` AS product_id,
ped.purchase_entry_id AS purchase_id,
p.`product-name` AS name,
m.name AS manufacturer,
p.`product-type` AS product_type,
ped.id AS batch_no,
ped.internal_sales_rate AS barcode,
c.name as category,
ped.size AS size,
IFNULL(ped.sales_rate,0) AS sales_rate,
IFNULL(ped.purchase_rate,0) AS purchase_rate,
IFNULL(SUM(ped.units),0) AS units_purchased,
IFNULL(sed.sum_qty),0) AS units_sold,
IFNULL(sr.sum_qty),0) AS retured,
IFNULL(pri.sum_qty),0) AS retured,
IFNULL(ast.sum_qty),0) AS adjustment,
IFNULL(ast.sum_batch_no),0) AS isChecked
FROM purchase_entry_details ped
LEFT JOIN products p on p.`product-id` = ped.product_id
LEFT JOIN category c ON c.id = p.`product-type`
LEFT JOIN manufacturer m ON m.id = p.manufacturer
LEFT JOIN
(
select batch_no, sum(qty) as sum_qty from sales_entry_details group by batch_no
) sed on sed.batch_no = ped.id
LEFT JOIN
(
select batch_no, sum(qty) as sum_qty from sales_return_item group by batch_no
) sr on sr.batch_no = ped.id
LEFT JOIN
(
select batch_no, sum(qty) as sum_qty from purchase_return_items group by batch_no
) pri on pri.batch_no = ped.id
LEFT JOIN
(
select batch_no, sum(qty) as sum_qty, sum(batch_no) as sum_batch_no
from adjustment_stock group by batch_no
) ast on ast.batch_no = ped.id
GROUP BY ped.id;
(Adding up batch numbers seems a bit weird, though.)

Answer 2

You can make separate joins for each table used in subqueries against purchase_entry_details table. In all these separate selects make group by ped.id. Afterwards make left join to new tables with sums.
SELECT
...
SED.sumqty,
SR.sumqty,
...
FROM purchase_entry_details ped
LEFT JOIN products p on p.`product-id` = ped.product_id
LEFT JOIN category c ON c.id = p.`product-type`
LEFT JOIN manufacturer m ON m.id = p.manufacturer
LEFT JOIN (
SELECT ped1.id, SUM(sed1.qty) as sumqty
FROM purchase_entry_details ped1
JOIN sales_entry_details sed1 ON sed1.batch_no = ped1.id
GROUP BY ped1.id
) SED ON SED.id = ped.id
LEFT JOIN (
SELECT ped1.id, SUM(sr1.qty) as sumqty
FROM purchase_entry_details ped1
JOIN sales_return_item sr1 ON sr1.batch_no = ped1.id
GROUP BY ped1.id
) SR ON SR.id = ped.id
...