检查结果后无法显示语句结果 [英] Displaying statement result doesn't work after checking results

问题描述

我已经编写了一个代码来从数据库中选择数据，并且我测试了该语句是否使用fetchColumn()返回了某项或否，如果使用fetch()进行了循环，则显示了结果是否为null.但是，即使结果存在，它也不会显示任何内容.这是我的代码:

I've wrote a code to select data from my database, and I test if the statement returns something or no with fetchColumn() and I display the results if it's not null using a loop with fetch(). But event when the results exist it soesn't show me anything.. Here's my code :

$req = $bdd->prepare('SELECT NOM_Etudiant, PRENOM_Etudiant FROM Etudiant WHERE CNE_Etudiant = :cnev AND PASS_Etudiant = :passv');
$req->execute(array('cnev' => $cne, 'passv' => $pass));

$count = $req->fetchColumn();
if(!$count) {
    header('Location: authentification_etud.php?status=invalid');
}
else {
    // Doesn't work
    while ($donnees = $req->fetch())
    {
        echo '<strong>Bienvenue </strong>' . $donnees['NOM_Etudiant'] . ' ' . $donnees['PRENOM_Etudiant'] . ' ! ' ;
    }
}

您知道为什么它不起作用吗?谢谢:)

Do you know why it doesn't work ? Thank you :)

推荐答案

您应该使用rowCount()方法来确定不是fetchColumn()的行数. fetchColumn()实际上会将指针移到结果集中，使您不再可以访问第一行数据.

You should use a rowCount() method to determine the number of rows not fetchColumn(). fetchColumn() will actually advance the pointer in the result set to where you will no longer have access to the first row of data.

请注意此页面上的红色大警告 http://php.net/manual/zh/pdostatement.fetchcolumn.php

Notice the big red warning on this page http://php.net/manual/en/pdostatement.fetchcolumn.php

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