Question

im试图在php中创建一个循环，弹出以下内容

$sqlons = "SELECT * FROM products WHERE ons = 1";
$ons = $db->query($sqlons);
$sqlpopa = "SELECT * FROM products WHERE popa = 1";
$popa = $db->query($sqlpopa);
$sqlnewr = "SELECT * FROM products WHERE newr = 1";
$newr = $db->query($sqlnewr);
$sqlpopm = "SELECT * FROM products WHERE popm = 1";
$popm = $db->query($sqlpopm);
$sqlpopm2 = "SELECT * FROM products WHERE popm = 2";
$popm2 = $db->query($sqlpopm2);
$sqlfeata = "SELECT * FROM products WHERE feata = 1";
$feata = $db->query($sqlfeata);
$sqlfeata2 = "SELECT * FROM products WHERE feata = 2";
$feata2 = $db->query($sqlfeata2);
$sqlbests = "SELECT * FROM products WHERE bests = 1";
$bests = $db->query($sqlbests);
$sqlbests2 = "SELECT * FROM products WHERE bests = 2";
$bests2 = $db->query($sqlbests2);
$sqlbests3 = "SELECT * FROM products WHERE bests = 3";
$bests3 = $db->query($sqlbests3);
$sqlsea = "SELECT * FROM products WHERE sea = 1";
$sea = $db->query($sqlsea);

我目前已经这样做

$vart = array("sqlons", "sqlpopa", "sqlnewr", "sqlpopm", "sqlfeata", "sqlbests", "sqlsea");
$vart2 = array("ons", "popa", "newr", "popm", "feata", "bests", "sea");
$var = array("ons", "popa", "newr", "popm", "popm", "feata", "feata", "bests", "bests", "bests", "sea");
$var2 = array("1", "1", "1", "1", "2", "1", "2", "1", "2", "3", "1");
foreach($var as $v){
    foreach($var2 as $v2){
        foreach($vart as $t){
            "$".$t = "SELECT * FROM products WHERE $v = $v2";
            foreach($vart2 as $t2){
            "$".$t2 = $db->query("$".$t);
            }
        }
    }
}

但是我得到了一个未定义的变量，例如“未定义的变量：C：\ xampp \ htdocs \ AniBuy \ pages \ index.php中的ons 在第90行”

请帮助我！：）

对不起，如果我添加了html / php代码，这可能会有所帮助

<?php while($product = mysqli_fetch_assoc($ons)) : ?>
                        <div class="<?= $product['class']; ?>">
                            <div class="grid-col-1">
                                <img class="featured-image img-responsive" src="<?= $product['img']; ?>">
                            </div>
                            <div class="grid-col-2">
                                <h2 class="featured-heading"><?= $product['title']; ?></h2>
                                <div class="grid-col-3">
                                    <div class="span-text"><?= $product['about']; ?><br></div><div class="buy-now"><a href="#">BUY NOW</a></div>
                                </div>
                            </div>
                        </div>
                    <?php endwhile; ?>

有不止一个，那么就有许多这样的论点从phpmyadmin数据库中吐出了img标题等

 <?php while($product = mysqli_fetch_assoc($popa)) : ?>
                            <div class="<?= $product['class']; ?>">
                            <div class="buy-now buy"><a href="#">BUY NOW</a></div>
                                <div h4 class="read-more" onclick="rmModal(<?= $product['id'];?>)"><a href="#rmModal-<?= $product['title'];?>.php">READ MORE</a></div>
                                <div class="featured-image"><img class="featured-image img-pop-anime img-responsive" src="<?= $product['img']; ?>"></div>
                            </div>
                            <?php endwhile; ?>
    <?php while($product = mysqli_fetch_assoc($newr)) : ?>
                        <div class="<?= $product['class']; ?>">
                            <div class="buy-now buy"><a href="#">BUY NOW</a></div>
                            <div h4 class="read-more" onclick="rmModal(<?= $product['id'];?>)"><a href="#rmModal-<?= $product['title'];?>.php">READ MORE</a></div>
                            <div class="grid-col-1"><img class="featured-image img-new" src="<?= $product['img']; ?>"></div>
                        </div>
                    <?php endwhile; ?>

到目前为止，我已经尝试过了

$vars = array("ons" => 1, "popa" => 1, "newr" => 1);
 foreach ($vars as $key => $value) {
"$"."sql".$key = "SELECT * FROM products WHERE $key = $value";
"$".$key = $db->query("$"."sql".$key);
// echo "$"."sql".$key;
// echo $value;
// echo "$".$key;
   }

但这仍然给我错误 mysqli_fetch_assoc（）期望参数1为mysqli_result，字符串在 C：\ xampp \ htdocs \ AniBuy \ pages \ index.php 在第142行

如果有人对网站的外观感兴趣，那么这里是仅包含html，css和js的网址：https://54x1.github.io/AniBuy/pages/indexv2.html

这是带有php和mysql的文件，我在anibuy文件夹旁边添加了sql导出，其文件夹是... / pages / index.php：https://drive.google.com/drive/folders/1mUYm2sH1bsxF3UaCxAvOIwTkubLCoVod?usp=sharing

Answer 1

您的问题是您正在使用字符串作为代码，例如：

"$".$t = "SELECT * FROM products WHERE $v = $v2";

和：

"$".$t2 = $db->query("$".$t);

您需要做的是将代码放入eval（）函数中，如下所示：

eval('$'.$t.' = "SELECT * FROM products WHERE $var$v = $v2";');

我认为您正在使用的所有foreach循环都会遇到另一个问题，我想因为所有数组都具有相同数量的元素，因此您应该执行以下操作：

for ($i=0; $i <count($vart) ; $i++) { 
    eval('$'.$vart[$i].' = "SELECT * FROM products WHERE $var[$i] = $var2[$i]";');
    eval("$".$vart2[$i] .'= $db->query("$".$vart[$i]);');
}

尝试一下，告诉我如何为您解决

Answer 2

在查询字符串中时，将$ v像这样的{$ v}换行。

您还应该重新设计阵列：

$vars = ["ons" => 1, "popa" => 1, ... ];
$results = [];
foreach($vars as $vkey => $vval){
   $results[$vkey] = $db->query("SELECT * FROM products WHERE {$vkey} = {$vval}")->fetch_assoc();
}

编辑：添加fetch_assoc（）调用，假设您只返回一行。否则，您将不得不使用嵌套的while：

$vars = ["ons" => 1, "popa" => 1, ... ];
$results = [];
foreach($vars as $vkey => $vval){
   $results[$vkey] = [];
   $result = $db->query("SELECT * FROM products WHERE {$vkey} = {$vval}");
    while($row=$result->fetch_assoc()){
        $results[$vkey][] = $row;
    }
}

Answer 3

在您的foreach循环中，$ v变量是什么？似乎没有在任何地方定义它。

"$".$t = "SELECT * FROM products WHERE $v = $v2";

Answer 4

给出您的评论，您已经有了正确的基本概念，但是实现实际上比您所拥有的要简单得多。首先，您的“控件”值，即数组$vart等采用的格式为Structure of Arrays，而使用结构数组可能会发现这容易得多。 / p>

数组结构存在的问题是，当您真的想同时并行处理所有四个数组时，有多个嵌套循环试图遍历它们-如果您使用结构数组。

因此，将数据更改为如下所示：

$vars = array(
    array(
        "select" => "ons",
        "compare" => "1",
        "result" => "ons"
    ),
    // etc. etc.
    array(
        "select" => "bests",
        "compare" => "2",
        "result" => "bests2"
    ),
    // ...

select处于SELECT子句的左侧，compare将是右侧，而result是数据到达的地方。

现在像这样制作循环：

foreach ($vars as $sqldata) {
    $select = $sqldata->select;
    $compare = $sqldata->compare;
    $result = $sqldata->result;
    $$result = $db->query("SELECT * FROM products WHERE $select = $compare");
}

是的，我的确在最后一行表示两个'$'。请注意，这将带您到达想要的地方。输入此变量之前，您需要做一些事情来使目标变量存在，否则，退出您的$$result循环后，foreach中的结果将超出范围。

或者，或者在开始之前创建一个空数组，然后将结果存储在该数组中。

Answer 5

在您这边触发的错误很奇怪，因为当我在一边运行您的代码时，我没有得到它。

在第一个数组中添加所有字段名称和值，其中 on 是字段名称，而 1 是 value < / em>用于where条件。为其他人做同样的事情。

$key =数据库中的字段名称

$value =字段名称的值

// As you have different values for bests, 1, 2, 3 and for others // If we used bests as index ex: array('bests' => 2, 'bests' => 3). The data // will be overwritten by the next bests as they have the same index. // 'fieldname_value' where fieldname = ons and value = 1 $vars = array('ons_1', 'bests_1', 'bests_2', 'bests_3'); $results = array(); foreach ($vars as $key => $value) { // Here I break the value which is ex: ons_1 into // an array(ons, 1). This will repeat for the other values. $values = explode('_', $value); $sql = "SELECT * FROM products WHERE $values[0] = $values[1]"; // $values[0] = fieldname $values[1] = value_of_fieldname $result = mysqli_query($db, $sql); if (mysqli_num_rows($result) > 0) { // output data of each row while($row = mysqli_fetch_assoc($result)) { $results[$value][] = $row; // Add all rows for fieldnames (ex: ons_1, bests_1, bests_2) inside $result array } } } /** * * First var_dump($results); to get a clearer view of what's going on below * * The array $results contain an array of arrays * Ex: $results = array ('ons_1' => array( 0 => array('class' => your_class), 'bests_1' => array( 0 => array('class' => your_class)) * * This if line checks whether the index exist isset($results['ons_1']) and if it is not empty !empty($results['ons_1']) * before doing the foreach loop. It would be unecessary to do a foreach loop that will trigger an error if ons_1 does * not exist and has no data. This is why this check is done. * * The foreach loop on the other hand will loop through all the data present in 'ons_1' array. var_dump($result['ons_1']); to * have an idea of what's going ons. * */ ?> <div class="grid-container container-fluid "> <div id="home-page" class="home-page"> <h2 class="featured-heading-2">On Sale Now!</h2> <div class="home-page-onsale"> <?php if (isset($results['ons_1']) && !empty($results['ons_1'])) { ?> <?php foreach ($results['ons_1'] as $key => $product) { ?> <div class="<?php echo $product['class']; ?>"> <div class="buy-now buy"><a href="#">BUY NOW</a></div> <div h4 class="read-more" onclick="rmModal(<?php echo $product['id']; ?>)"><a href="#rmModal-<?php echo $product['title']; ?>.php">READ MORE</a></div> <div class="grid-col-1"><img class="featured-image img-new" src="<?php echo $product['img']; ?>"></div> </div> <?php } ?> <?php }?> </div> <div class="breakpoint-3"> <div class="home-page-best-anime"> <h2 id="home-page-best-anime bpshow" class="featured-heading-2">Best Sellers</h2> <div class="home-page-best-anime-row-1"> <?php if (isset($results['bests_1']) && !empty($results['bests_1'])) { ?> <?php foreach ($results['bests_1'] as $key => $product) { ?> <div class="<?php echo $product['class']; ?>"> <div class="buy-now buy"><a href="#">BUY NOW</a></div> <div h4 class="read-more" onclick="rmModal(<?php echo $product['id']; ?>)"><a href="#rmModal-<?php echo $product['title']; ?>.php">READ MORE</a></div> <div class="grid-col-1"><img class="featured-image img-new" src="<?php echo $product['img']; ?>"></div> </div> <?php } ?> <?php }?> </div> <div class="home-page-best-anime-row-2"> <?php if (isset($results['bests_2']) && !empty($results['bests_2'])) { ?> <?php foreach ($results['bests_2'] as $key => $product) { ?> <div class="<?php echo $product['class']; ?>"> <div class="buy-now buy"><a href="#">BUY NOW</a></div> <div h4 class="read-more" onclick="rmModal(<?php echo $product['id']; ?>)"><a href="#rmModal-<?php echo $product['title']; ?>.php">READ MORE</a></div> <div class="grid-col-1"><img class="featured-image img-new" src="<?php echo $product['img']; ?>"></div> </div> <?php } ?> <?php }?> </div> <div class="home-page-best-anime-row-3"> <?php if (isset($results['bests_3']) && !empty($results['bests_3'])) { ?> <?php foreach ($results['bests_3'] as $key => $product) { ?> <div class="<?php echo $product['class']; ?>"> <div class="buy-now buy"><a href="#">BUY NOW</a></div> <div h4 class="read-more" onclick="rmModal(<?php echo $product['id']; ?>)"><a href="#rmModal-<?php echo $product['title']; ?>.php">READ MORE</a></div> <div class="grid-col-1"><img class="featured-image img-new" src="<?php echo $product['img']; ?>"></div> </div> <?php } ?> <?php }?> </div> </div> </div> </div> </div>

我正在尝试在php中制作一个循环，以吐出下面的内容

5 个答案: