selectOne should use fetch directly instead of array_shift

[haidubogdan]

I always found this thing very peculiar.
If we want to fetch one row, the default laravel framework logic is:

we execute a query -> fetchAll rows -> and shift the first element of the array.

I see this having some performance issues and risks. Imagine we have a table with 10 000 rows and a beginner is thinking, that we have the selectOne method just to take just the first row from it.

Yet by using the existing method he will probably get a memory exception or a very big latency issue as we are filling an array with 10 000 rows, just to get the first result.

Pdo already has the fetch method which will return just one row from the query.

https://www.php.net/manual/en/pdostatement.fetch.php

So maybe it can be used in the following laravel updates.

    /**
     * Run a select statement and return a single result.
     *
     * @param  string  $query
     * @param  array  $bindings
     * @param  bool  $useReadPdo
     * @return mixed
     */
    public function selectOne($query, $bindings = [], $useReadPdo = true)
    {
        $records = $this->select($query, $bindings, $useReadPdo);

        return array_shift($records);
    }

I've avoided to label this Idea an issue as it all boils down to how the user uses his application.
And I'm surprised that nobody complained about this yet.

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How to reproduce

It's easy to reproduce a memory exhaustion exception. Fill in a table with 10.000 rows and use selectOne with a raw query.