GROUP sum BY two tables by joining - mysql

Question

I'm trying to write a SQL query that will correctly group sales items sold_qyt and sub-total-price together as per product's category so I can show this on the printable invoice that product from Jelly Sheet = 4 at a rate of 62 subtotal for this category product is 248(4 * 62 = 248). but when I try to run the below-mentioned query it shows out-put as 12 but I want subtotal and sold_qyt segregated base on category.
I have tried to run different queries just one query gives the output which is mentioned below and this is for just the sum of all sold_qyt. DB example is also shown below
DB Example: (For better understanding)
Table # 1:
Category
ID | code | name
1 | 1 | jelly sheet
2 | 2 | 9D Glass
3 | 3 | Polished Glass
Table # 2:
Product:
ID | code | name | cost | category_id | price
1 | 1 | IP11JS | 50 | 1 | 62
2 | 2 | IP12JS | 50 | 1 | 62
3 | 3 | IP119D | 40 | 2 | 55
4 | 4 | IP129D | 40 | 2 | 55
5 | 5 | IP11PG | 18 | 3 | 25
6 | 6 | IP12PG | 18 | 3 | 25
Table # 3:
sale_items:
ID | sale_id | product_id | product_code | product_name | unit_price | sold_qyt | subtotal |
1 | 1 | 1 | 1 | IP11JS | 62 | 2 | 124 |
2 | 1 | 2 | 2 | IP12JS | 62 | 2 | 124 |
3 | 1 | 3 | 3 | IP119D | 55 | 2 | 110 |
4 | 1 | 4 | 4 | IP129D | 55 | 2 | 110 |
5 | 1 | 5 | 5 | IP11PG | 25 | 2 | 50 |
6 | 1 | 6 | 6 | IP12PG | 25 | 2 | 50 |
7 | 2 | 7 | 1 | IP11JS | 62 | 2 | 124 |
8 | 2 | 8 | 2 | IP12JS | 62 | 2 | 124 |
9 | 2 | 9 | 3 | IP119D | 55 | 2 | 110 |
10 | 2 | 10 | 4 | IP129D | 55 | 2 | 110 |
11 | 2 | 11 | 5 | IP11PG | 25 | 2 | 50 |
12 | 2 | 12 | 6 | IP12PG | 25 | 2 | 50 |
SQL Query which is run by me:
SELECT sale_id,
SUM(sold_qyt) AS sold_qyt
FROM sale_items
GROUP BY sale_id
kindly help me with this difficulty thanks in advance
Update: 1-21-2021
i execute new query
SELECT (sma_sale_items.sale_id, sma_categories.code AS sma_products.category_id, sma_products.code AS sma_sale_items.product_code,)
SUM(sold_qyt) AS sold_qyt
SUM(subtotal) AS subtotal
FROM sma_sale_items
LEFT JOIN sma_products ON sma_products.id=sma_sale_items.product_id
LEFT JOIN sma_categories ON sma_categories.code=sma_products.category_id
GROUP BY sma_sale_items.sale_id
ORDER BY sma_categories
but no luck :(
I want the output like this:
Expected OUT PUT:
ID | sale_id | category_name | sold_qyt | subtotal |
1 | 1 | Jelly Sheet | 4 | 248 |
2 | 1 | 9D Glass | 4 | 220 |
3 | 1 | Polished Glass | 4 | 100 |
4 | 2 | Jelly Sheet | 4 | 248 |
5 | 2 | 9D Glass | 4 | 220 |
6 | 2 | Polished Glass | 4 | 100 |

Answer 1

The ID column in your expected result set is very misleading - it appears to be just new ID value for the output result set rather than any of the ID values from the source tables.
If it is important for you then you can use this query:
SELECT ROW_NUMBER() OVER (ORDER BY sale_id, category_id),
sale_id,
category_name,
sold_qty,
subtotal
FROM (
SELECT c.ID as category_id,
si.sale_id,
c.[name] as category_name,
SUM(si.sold_qty) as sold_qty,
SUM(si.subtotal) as subtotal
FROM sale_items si
JOIN product p ON p.ID = si.product_code
JOIN category c ON c.ID = p.category_id
GROUP BY c.ID,
si.sale_id,
c.[name]
) r
If it is not relevant and you only want the sale_id, category_name and the totals then simplify it to:
SELECT si.sale_id,
c.[name] as category_name,
SUM(si.sold_qty) as sold_qty,
SUM(si.subtotal) as subtotal
FROM sale_items si
JOIN product p ON p.ID = si.product_code
JOIN category c ON c.ID = p.category_id
GROUP BY si.sale_id,
c.[name]
ORDER BY sale_id, category_name