为什么求和大数据不起作用？ （Laravel 5.3）

My code, you can see this below :

public function total()
{
    $query = User::limit(100000)->get();
    $total = $query->sum('total');
    dd($total);
}

The result of dd($total) not display or empty

But when I change limit(50000), it display the result

Why it does not work if limit(100000)?

Note :

In firefox browser, it does not display anything

In chrome browser, it display error :

This page isn’t working

myshop.dev is currently unable to handle this request. HTTP ERROR 500

When you call get, you are fetching all this records from the database. And then performing the sum with php. You are probably having a timeout when fetching that much records from the database.

Why don't you perform the sum in the database, and then fetch the result?

public function total()
{
    $total = User::limit(100000)->sum('total');
    dd($total);
}

----- edit -----

When you perform:

$query = User::limit(100000)->get();

The $query variable actually holds the result set of the query select * from user limit 100000. The result set its a collection (see collect), then you are performing a sum on the server-side, something equivalent to:

$sum = 0;
foreach ($user in $query) {
    $sum = $sum + $user->total;
}

It's better to perform the sum in the database using the proper aggregate function.

$total = User::limit(100000)->sum('total'); would translate to:

select SUM(total) from user limit 1000000

If the result is 0, probably all your result set for the column total is actually 0.