php - 如何在foreach循环内求和计数查询？

Question

<?php 
    foreach($idd as $ids)
    {
        $sql5 = "select count(DISTINCT product_name) as total from stock where type = '".$ids."'";
        $result5 = mysqli_query($con,$sql5);
        $row5 = mysqli_fetch_row($result5);
    }
    $total5 = $row5[0];
?>

在这段代码中，我为 $idd 使用了 explode 函数，并在 foreach 循环内运行查询，并希望在 foreach 循环内对多个查询求和，现在，我的查询如下所示:

select count(DISTINCT product_name) as total from stock where type = 'Green Tea'select count(DISTINCT product_name) as total from stock where type = 'Herbal Tea'

但是我想要这样

select (select count(DISTINCT product_name) as total from inventory_add_in_stock where type = 'Green Tea')+(select count(DISTINCT product_name) as total from inventory_add_in_stock where type = 'Herbal Tea') as total

那么，我该怎么做呢？请帮助我。

谢谢

Answer 1

您需要在 foreach() 中获取值并将它们相加。像下面这样:-

<?php

    $total_count = 0; // a varible define to get total count in last
    foreach($idd as $ids)
    {
        $sql5 = "select count(DISTINCT product_name) as total from stock where type = '".$ids."'";
        $result5 = mysqli_query($con,$sql5) or die(mysqli_error($con));
        $row5 = mysqli_fetch_assoc($result5);
        $total_count += $row5['total']; // add counts to variable
    }
    echo $total_count; // print final count
?>

您的代码对SQL INJECTION 是开放的。尝试使用准备好的语句

mysqli_prepare()

PDO::prepare

注意:-尽量不要循环

https://dba.stackexchange.com/a/102345