從SQL語句中回傳數據

Question

我對PHP和SQL語句並不陌生，但是我偶然發現了這個問題，並且對如何解決這個問題感到不知所措。我的查詢不像我想要的那樣顯示commentID。

<?php 
    $query = "SELECT `commentID`, `blogID` FROM blog_comments WHERE blogID = ':postid' ORDER BY commentID DESC LIMIT 1"; 
    $query_params = array(':postid' => $row['postID']); 
try { 
    $stmt = $db->prepare($query); 
    $result = $stmt->execute($query_params); 
} 
catch(PDOException $e) 
{ 
    die($e->getMessage()); // Don't echo $e on prod. site 
} 
$rows = $stmt->fetchAll(); 
?> 
<?php foreach($rows as $row): ?> 
    <?php echo $row['commentID']; ?> 
<?php endforeach; ?> 
comments 

Answer 1

在WHERE blogID = ':postid'

刪除引號被視爲string literal

WHERE blogID = :postid 

做錯誤檢查會發現這一點。

• http://php.net/manual/en/pdo.error-handling.php

參考文獻：

• http://php.net/manual/en/pdo.prepared-statements.php
• http://php.net/manual/en/language.types.string.php
• https://dev.mysql.com/doc/refman/5.0/en/string-literals.html