exists query does not return relevant result - sql

Question

I have a Laravel application with this Eloquent query:
$products = Product::where('name', 'LIKE', "%{$value}%")
->whereHas('categories', function($q) {
$q->where( 'slug', 'tonery-cartridge' );
})->with('manufacturer')
->with('sm_image')
->orderBy('created_at','DESC')
->take(10)
->get();
This code generates the sql command like:
select * from `products` where `name` LIKE '%can%'
and exists (
select * from `categories` inner join `category_product`
on `categories`.`id` = `category_product`.`category_id`
where `products`.`id` = `category_product`.`product_id`
and `slug` = 'tonery-cartridge'
)
order by `created_at` desc limit 10
I am sure there are products which name contains "can" string and which belongs to the category with slug "tonery-cartridge". Why this query returns an empty result? If I try to make inner join sql manually it works well as on the screenshot below:

Answer 1

I think that your queries are not equivalent. The SQL output from laravel does not join tables in it's FROM clause, but in your manually constructed SQL statement you do a lot of inner joins in your FROM clause and on the resulting table you perform your operations, which is not true for the former.
Try the following
DB::table('products')
->join('category_product', 'category_product.product_id', '=', 'products.id')
->join('categories', 'category_product.category_id', '=', 'categories.id')
->whereRaw('products.name LIKE %can% AND categories.slug = "tonery-cartridge"')
->select('products.name', 'categories.slug')
->orderBy('created_at','DESC')
->take(10)
->get()
If you want to avoid using whereRaw, you can try the following.
DB::table('products')
->join('category_product', 'category_product.product_id', '=', 'products.id')
->join('categories', 'category_product.category_id', '=', 'categories.id')
->where([
['products.name, 'LIKE', '%' . $value . '%'],
['categories.slug', '=', 'tonery-cartridge']])
->select('products.name', 'categories.slug')
->orderBy('created_at','DESC')
->take(10)
->get()
HTH

Answer 2

This could be one of the solutions
$category = Category::where( 'slug', 'tonery-cartridge' )->first();
$products = $category->products()
->where('name', 'LIKE', "%{$value}%")
->with('manufacturer')
->with('sm_image')
->latest()
->take(10)
->get();