Convert DB::Select to Query Builder - laravel

Question

i has raw query in laravel like this
public function getPopularBook(){
$book = DB::select("
with totalReview as(
SELECT r.book_id , count(r.id)
FROM review r
GROUP BY r.book_id
)
SELECT *
from totalReview x
left JOIN (
SELECT b.*,
case when ((now() >= d.discount_start_date and now() <= d.discount_end_date) or (now() >= d.discount_start_date and d.discount_end_date is null)) then (b.book_price-d.discount_price)
ELSE b.book_price
end as final_price
FROM discount d
right JOIN book b
on d.book_id = b.id
) as y
on x.book_id = y.id
ORDER BY x.count DESC, y.final_price ASC
LIMIT 8"
);
return $book;
}
so when i want to return a paginate, it doesn't work so can i convert this to query build to use paginate

Answer 1

This is a very un-optimized raw query in itself. You are performing too many Join in Subquery just to sort by price
i'm assuming the database table:
books[ id, name, price ]
reviews[ id, book_id ]
discounts[ id, book_id, start_date, end_date, discount_price]
Look how easy it is if you just use Eloquent:
Book::withCount('reviews')->orderBy('reviews_count')->get();
this will give you all the Books order by number of reviews
now with the final price, this can be a bit tricky, let's take a look at a query when we don't consider discount time
Book::withCount('reviews')
->withSum('discounts', 'discount_price') //i'm assuming a book can have many discount at the same time, so i just sum them all
->addSelect(
DB::raw('final_price AS (books.price - discounts_sum_discount_price)')
)
->orderBy('reviews_count', 'asc') // =you can specify ascending or descending
->orderBy('final_price', 'desc') //in laravel chaining multiple orderBy to order multiple column
->get();
I dont even need to use Subquery!! But how do we actually only add the "active" discount?, just need to modify the withSum a bit:
Book::withCount('reviews')
->withSum(
[
'discounts' => function($query) {
$query->where('start_date', '<=', Carbon::now())
->where('end_date', '>=', Carbon::now())
}
],
'discount_price'
)
->addSelect(
DB::raw('final_price AS (books.price - discounts_sum_discount_price)')
)
->orderBy('reviews_count', 'asc') // =you can specify ascending or descending
->orderBy('final_price', 'desc') //in laravel chaining multiple orderBy to order multiple column
->get();
and it is done
What about pagination? just replace the get() method with paginate():
Book::withCount('reviews')
->withSum(['discounts' => function($query) {
$query->where('start_date', '<=', Carbon::now())->where('end_date', '>=', Carbon::now())
}],'discount_price')
->addSelect(DB::raw('final_price AS (books.price - discounts_sum_discount_price)')) //just format to be a bit cleaner, nothing had changed
->orderBy('reviews_count', 'asc')
->orderBy('final_price', 'desc')
->paginate(10); //10 books per page
WARNING: this is written with ELoquent ORM, not QueryBuilder, so you must define your relationship first