Mysql fetch rows limited be another table column value - mysql

Question

I have list of products and seller who added this products
Each Seller has a limit to show the products.
I need to write a query to list all the products with pagination 100 and show only seller products limited to that seller
`Seller Table`
| seller id| Seller Name | limit |
|:-------- |:-----------:| ------:|
| 1 | Seller One | 1 |
| 2 | Seller Two | 3 |
| 3 | Seller Three| 2 |
`Products Table
| product id| seller id | Product Name |
|:-------- |:----------:| ------------:|
| 1 | 1 | Product 1 |
| 2 | 2 | Product 2 |
| 3 | 1 | Product 3 |
| 4 | 1 | Product 4 |
| 5 | 2 | Product 5 |
| 6 | 2 | Product 6 |
| 7 | 2 | Product 7 |
| 8 | 3 | Product 8 |
| 9 | 3 | Product 9 |
| 9 | 3 | Product 10 |
| 9 | 3 | Product 11 |
(Output or Result I am expecting)
| product id| seller id | Product Name |
|:-------- |:----------:| ------------:|
| 1 | 1 | Product 1 |
| 2 | 2 | Product 2 |
| 5 | 2 | Product 5 |
| 6 | 2 | Product 6 |
| 8 | 3 | Product 8 |
| 9 | 3 | Product 9 |
Seller 1 = Product 1
Seller 2 = Product 2 , Product 5 and Product 6
Seller 3 = Product 8 and Product 9
I want to get this products
How do I write a query?
and also is it possible to selected random products of the seller
I have query only to fetch only the products.
$products = Products::paginate(100);
```
I need modify it based on Seller Model

Answer 1

Enable WHERE clause when searching particular seller and product otherwise disable it. Use LIMIT and OFFSET for pagination. Please try this
-- MySQL (v5.8)
SELECT t.product_id, s.seller_id, t.product_name
FROM seller s
INNER JOIN (SELECT product_id
, seller_id
, product_name
, ROW_NUMBER() OVER (PARTITION BY seller_id ORDER BY product_id) row_num
FROM Products
-- WHERE seller_id = 1
-- AND product_id = 1
) t
ON s.seller_id = t.seller_id
AND t.row_num <= s.t_limit;
Please check from url https://dbfiddle.uk/?rdbms=mysql_8.0&fiddle=d142f50fb24763ec9fc1e937f8b8d6a7
If needed comma separated product_name then try this one
SELECT CONCAT(MAX(s.seller_name), ' = ', GROUP_CONCAT(t.product_name)) expected_output
FROM seller s
INNER JOIN (SELECT product_id
, seller_id
, product_name
, ROW_NUMBER() OVER (PARTITION BY seller_id ORDER BY product_id) row_num
FROM Products
-- WHERE seller_id = 1
-- AND product_id = 1
) t
ON s.seller_id = t.seller_id
AND t.row_num <= s.t_limit
GROUP BY s.seller_id;
Please check from https://dbfiddle.uk/?rdbms=mysql_8.0&fiddle=0e4cfa7dbb744e7aa416b79d6f964775

Answer 2

As per #RahulBiswas sql code I wrote a Laravel Query. It is working
$subq = Products::select(DB::raw('ROW_NUMBER() OVER (PARTITION BY seller_id ORDER BY id) row_num, *'));
$query = Sellers::select('t.*',)->join(\DB::raw('('.$subq->toSql().') as t'), function ($join) use ($subq) {
$join->on('sellers.user_id','t.seller_id')
$join->on('t.row_num', '<=', "sellers.limit")
})