monthsBetween.php

<?php

function monthly($from, $to)
{
    $months = $this->monthsBetween($from, $to);
    $salesData = [];
    
    if (count($months) > 6) {
        return null;
    }
    
    foreach ($months as $month) {
        $orderIds = json_decode(json_encode($this->getOrderIds($month)), true);
        
        if (count($orderIds) > 0) {
            $orderTotal = (array)$this->sqlDatabaseManager
                                ->table('order_totals')
                                ->select($this->sqlDatabaseManager->raw('
                                    CAST(SUM(`cost`) as UNSIGNED) as `cost`,
                                    CAST(SUM(`subtotal`) as UNSIGNED) as `subtotal`,
                                    CAST(SUM(`shipping_fee`) as UNSIGNED) as `shipping_fee`,
                                    CAST(SUM(`payment_fee`) as UNSIGNED) as `payment_fee`,
                                    CAST(SUM(`wrapping_total`) as UNSIGNED) as `wrapping_total`,
                                    CAST(SUM(`sum`) as UNSIGNED) as `sum`,
                                    CAST(SUM(`points_discount`) as UNSIGNED) as `points_discount`,
                                    CAST(SUM(`total`) as UNSIGNED) as `total`
                                '))
                                ->whereIn('order_id', $orderIds)
                                ->orderBy($this->sort, $this->direction)
                                ->skip($this->offset)
                                ->take($this->limit)
                                ->first();

            $orderTotal['date'] = $month;
            $salesData[] = $orderTotal;
        }
    }
    
    return $salesData;
}

function monthsBetween($from, $to) {
	$from  = (int)strtotime($from);
	$to    = (int)strtotime($to);
	$dates = $from < $to ? [$from, $to] : [$to, $from];

	$fromDate = date('Y-m', $dates[0]);
	$toDate   = date('Y-m', $dates[1]);

	// calculate months between
	$months = [];
	while (true) {
		$currentDate = date('Y-m', (int)strtotime('+' . $monthsBetween . ' month', (int)strtotime($fromDate)));

        if ($currentDate === $toDate || count($months) > 6) {
			return $months;
		}

		$months[] = $currentDate;
	}
}