I am getting weird behaviour and not sure if it is something I am doing wrong or a bug in Laravel query builder.

Whenever I am using the Builder::whereNotNull method, I seem to always have at least one extra WHERE NOT NULL statement in my query.

Example Code:

Method to sync all the customer contacts:

public function doStuff(CustomerRepository $customers)
{
    $count = $customers->count();

    $pages = (integer) ceil($count / $this->pageSize);

    for ($page = 0; $page < $pages; $page++) {
        $contacts = $customers->page($page * $this->pageSize, $this->pageSize);
        // yada-yada
    }
}

Relevant methods in the Customer Repository class:

public function __construct(DatabaseManager $databaseManager)
{
    $this->customers = $databaseManager->connection('sqlsrv')
        ->table('dbo.entity as Contact')
        ->select($this->select)
        ->leftJoin('dbo.entity AS Parent', 'Contact.COMPANY_ID', '=', 'Parent.ENTITY_ID')
        ->whereNotNull('Contact.email');
}

public function page($offset = 0, $count = 1000)
{
    if ($count > 1000) {
        $count = 1000;
    }

    return $this->customers
        ->skip($offset)
        ->take($count)
        ->get();
}

Eventually results in a query like this:

    select * from (
        select [Contact].[email],
            [Parent].*,
            row_number() over (order by (select 0)) as row_num
        from [dbo].[entity] as [Contact]
        left join [dbo].[entity] as [Parent] on [Contact].[COMPANY_ID] = [Parent].[ENTITY_ID]
        where [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null and [Contact].[email] is not null
        ) as temp_table
    where row_num between 64001 and 65000