PHP:获取mysql列中的最高和最低值? [英] PHP: get the highest and lowest value in a mysql column?

问题描述

我正在尝试获取 mysql 列中的最高和最低值，但我不知道这是否可能！

I'm trying to get the highest and lowest value in a mysql column but I hav eno idea if this is even possible!

我在官方 MYSQL 论坛中遇到了这段代码，但我真的不知道如何将这些值作为 PHP 变量获取！

I came across this code in the official MYSQL forum but I really don't know how to get those values as PHP variables!

SELECT
(SELECT `price` FROM mytable ORDER BY `price` LIMIT 1) AS lowest,
(SELECT `price` FROM mytable ORDER BY `price` DESC LIMIT 1) AS highest

所以基本上我需要做的是从那个 mysql 查询创建 PHP 变量，并获得最高值 $hiestprice 和最低值 $lowestprice

so basically what i need to do is to create PHP variables from that mysql quesry and to just get the highest value as $hiestprice and the lowest as $lowestprice

所以我继续前进，我做到了:

so i went ahead and I did:

$sql = "SELECT
    (SELECT `price` FROM mytable ORDER BY `price` LIMIT 1) AS lowest,
    (SELECT `price` FROM mytable ORDER BY `price` DESC LIMIT 1) AS highest";
$query = mysqli_query($db_conx, $sql);
$productCount = mysqli_num_rows($query ); // count the output amount
if ($productCount > 0) {
    while($row = mysqli_fetch_array($query, MYSQLI_ASSOC)){

$hiestprice = $row['price'];
$lowestprice = $row['price'];

}

}

但这是错误的，当我回显 $hiestprice 和 $lowestprice 时，我的 PHP 页面上没有任何返回！

But that is wrong and I get nothing returned on my PHP page when I echo the $hiestprice and $lowestprice!

有人能指出我正确的方向吗?

Could someone please point me in the right direction ?

推荐答案

首先可以优化查询使用

SELECT MIN(  `price` ) AS  `lowest` , MAX(  `price` ) AS  `highest` FROM  `mytable`

比你可以使用的价格

$highestprice = $row['highest'];
$lowestprice = $row['lowest']

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