PHP:获取mysql列中的最高和最低值？

Question

我想在mysql专栏中获得最高和最低价值,但我想知道这是否可能!

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!

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mysql问题创建PHP变量,并获得最高值$hiestprice和最低值$lowestprice

所以我继续前进,我做了:

$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,当我回应$hiestprice和时,我的PHP页面上没有返回任何内容$lowestprice!

有人可以指点我正确的方向吗？

Answer 1

首先,您可以优化查询和使用

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']