如何循环遍历 PHP 中的 sql sum 结果？

Question

我需要总结总计列的结果：SELECT SUM(number_guest) AS total, booking_time   FROM mt_bookingtable   WHERE            merchant_id IN (SELECT merchant_id                               FROM mt_merchant                               WHERE merchant_id = 1 )            AND booking_time BETWEEN "12:00" AND "20:00"            AND            date_booking like "2020-06-01"            AND status in ('pending','approved')   GROUP BY booking_time结果我试图像这样使用 foreach：foreach ($res as $item) {    $sum += $item['total'];    return $sum;}但我得到了结果null。

Answer 1

删除GROUP BY：

SELECT SUM(number_guest) AS total

FROM mt_bookingtable

WHERE merchant_id IN (SELECT merchant_id FROM mt_merchant WHERE merchant_id = 1 ) AND

      booking_time BETWEEN '12:00' AND '20:00' AND

      date_booking like '2020-06-01' AND

      status in ('pending', 'approved');