Calculated fields in Laravel using Query Builder - php

Question

I've been working in a Laravel Project and I want to know how can I show a calculated field in a blade view? I want to retrieve some information from an invoice and a Total calculated field.
I would like to get this result, but using Eloquent ORM. The query is this:
SELECT
invoiceheader.id,
invoiceheader.customerlastname,
invoiceheader.customerfirstname,
invoiceheader.customernit,
invoicedetail.productid,
invoicedetail.quantity,
invoicedetail.saleprice,
(quantity * saleprice) as Total
FROM invoiceheader
INNER JOIN invoicedetail
ON invoiceheader.id = invoicedetail.invoiceid
Thank you so much in advance.

Answer 1

You can use laravels DB::raw(), which injects the string to the query, like so:
Laravel raw expressions
InvoiceHeader::select('invoiceheader.id', 'invoiceheader.customerlastname',
'invoiceheader.customerfirstname', 'invoiceheader.customernit',
'invoicedetail.productid', 'invoicedetail.quantity',
'invoicedetail.saleprice', DB::raw('(quantity * saleprice) as Total'))
->join('invoicedetail', 'invoiceheader.id', '=', 'invoicedetail.invoiceid')
->get();
Note: make sure to import use DB; on the top of the page

Answer 2

You can do this by utlizing Eloquent relations and accessors.
In your InvoiceHeader model:
/*
Relation with the invoicedetail table
*/
public function detail()
{
return $this->hasOne(InvoiceDetail::class, 'invoiceid', 'id');
}
In your InvoiceDetail model:
/*
The accessor field
*/
protected $appends = ['total_price'];
/*
Accessor for the total price
*/
public function getTotalPriceAttribute()
{
return $this->quantity * $this->saleprice;
}
To understand the created accessor name from the method name, here's a text from the laravel docs:
To define an accessor, create a getFooAttribute method on your model
where Foo is the "studly" cased name of the column you wish to access.
In this example, we'll define an accessor for the first_name
attribute. The accessor will automatically be called by Eloquent when
attempting to retrieve the value of the first_name attribute:
For your query you could do:
// get all invoices in descending order of creation
$invoices = InvoiceHeader::recent()->get();
// loop invoice data to get the desired fields
foreach ($invoices as $invoice) {
$customerfirstname = $invoice->customerfirstname;
$totalprice = $invoice->detail->total_price;
// more code
}
You can read more about Accessors & Mutators on the official documentation here. Read about eloquent relations here.

Answer 3

Try this
InvoiceHeader::join("invoicedetail",function($query){
$query->on("invoiceheader.id", "=", "invoicedetail.invoiceid")
})
->select("invoiceheader.id",
"invoiceheader.customerlastname",
"invoiceheader.customerfirstname",
"invoiceheader.customernit",
"invoicedetail.productid",
"invoicedetail.quantity",
"invoicedetail.saleprice",
\DB::raw("(invoicedetail.quantity * invoicedetail.saleprice) as Total"))
->get();