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嗨，我正在尝试使用 foreach 循环从我的数据库中的表中回显行

我就是这样做的

//连接数据库//

$stmt_seven = $db->prepare('SELECT img, description FROM Videos ORDER BY date LIMIT 10;');
$stmt_seven->execute();
$res_seven = $stmt_seven->fetchAll(PDO::FETCH_NUM);
<?php
    if(!$res_seven)
    {
        echo "<br />";
        echo"No Content Available Yet..";
    }
    else
        foreach($res AS $val)
        {
            foreach($val AS $val1)
            {
                **echo "$val1['img'];
                echo "$val1['description'];**    
            }
        }
    $db = null;
?>

突出显示的代码不起作用。而且我不知道我做错了什么！

4

3 回答 3

1 
$res_seven = $stmt_seven->fetchAll [...]
foreach($res as ...

什么是 $res？

foreach( $resultOfFetchAll as $val) {
  foreach($val as $val1) {
    // now $val1 is the value of a single column, i.e. a scalar or a string
    // but you're trying to access as if it was a row / array
  }
}

您可以简单地将PDOStatement对象本身传递给 foreach，而不是使用 fetchAll() 然后迭代该数组，因为它实现了可遍历接口。例如

<?php
function foo($db) {
    $stmt = $db->query('SELECT img, description FROM Videos ORDER BY date LIMIT 10', PDO::FETCH_ASSOC);
    foreach( $stmt as $row ) {
        echo $row['img'], ' - ', $row['description'], "<br />\n";
    }
    if ( 0===$stmt->rowCount() ) {
        echo "no data yet<br />\n";
    }
    echo "---<br />\n";
}

$db = new PDO('sqlite::memory:', null, null);
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$db->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
setup($db, false);
foo($db);
setup($db, true);
foo($db);

// boilerplate/data-source for self-contained example
function setup($pdo, $populate) {
    if ( !$populate ) {
        $pdo->exec('
            CREATE TABLE Videos (
                img,
                description,
                date
            )
        ');
    }
    else {
        $stmt = $pdo->prepare('INSERT INTO Videos (img,description,date) VALUES (?,?,?)');
        for($i=1; $i<21; $i++) {
            $stmt->execute(array(
                sprintf('img%02d', $i),
                sprintf('desc%02d', $i),
                sprintf('2012-01-%02d 12:00:00', $i)
            ));
        }
    }
}

印刷

no data yet<br />
---<br />
img01 - desc01<br />
img02 - desc02<br />
img03 - desc03<br />
img04 - desc04<br />
img05 - desc05<br />
img06 - desc06<br />
img07 - desc07<br />
img08 - desc08<br />
img09 - desc09<br />
img10 - desc10<br />
no data yet<br />
---<br />
于 2013-01-28T12:10:51.910 回答
1

根据代码，您的 $res 为空。我想应该是 $res_seven

去掉echo "$val1['img']; echo "$val1['description'];中的双引号 

$stmt_seven = $db->prepare('SELECT img, description FROM Videos ORDER BY date LIMIT       
10;');
$stmt_seven->execute();
$res_seven = $stmt_seven->fetchAll(PDO::FETCH_NUM);
if(!$res_seven){
echo "<br />";
echo"No Content Available Yet..";
}
else
foreach($res AS $val) {
foreach($val AS $val1) {
**echo "$val1['img'];
echo "$val1['description'];**    
}
}
$db = null;
?>
于 2013-01-28T11:51:30.700 回答
1

除了其他人已经指出的错字之外，您使用PDO::FETCH_NUM的是“返回一个按列号索引的数组，如结果集中返回的那样，从第 0 列开始”。

根据您想要的代码PDO::FETCH_ASSOC，“返回由结果集中返回的列名索引的数组”

或者，您可以将其留空并使用默认值PDO::FETCH_BOTH“返回由列名和 0 索引列号索引的数组，如结果集中返回的那样”

来源： http: //php.net/manual/en/pdostatement.fetch.php

于 2013-01-28T12:00:07.213 回答