PDO - 從Select語句

Question

顯示行我一直在掙扎了一段時間才能得到下面的代碼運行，它不是返回任何東西：

try { 
    $DBH = new PDO("mysql:host=$dbHost;dbname=$dbDatabase", $dbUser, $dbPass); 
    $DBH->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); 
    $STH = $DBH->prepare('SELECT * FROM `component`'); 
    # setting the fetch mode 
    $STH->setFetchMode(PDO::FETCH_ASSOC); 

    while($row = $STH->fetchAll()) { 
    echo $row['cid'] . "\n"; 
    echo $row['cdesc'] . "\n"; 
    echo $row['cinfo'] . "\n"; 
    } 
} 
catch(PDOException $e) { 
    echo "I'm sorry. I'm afraid I can't do that."; 
    echo $e->getMessage(); 
} 

任何援助將不勝感激。 RGDS，燉

Answer 1

您錯過了execute方法。 fetchAll的錯誤用法。

見Example #1 Fetch all remaining rows in a result set

又如與fetchMode：

$STH = $DBH->prepare('SELECT * FROM `component`'); 
$STH->execute(); 
$STH->setFetchMode(PDO::FETCH_ASSOC); 

// since PDOStatement implements Traversable you can directly iterate 
foreach ($STH as $row) { 
    echo $row['cid'] . "\n"; 
} 

Answer 2

fetchAll返回所有的行，如果你想遍歷結果，你可以使用：

while($row = $STH->fetch()) 

或者，如果你想堅持fetchAll()：

$rows = $STH->fetchAll(); 
foreach($row in $rows){ 
    ... 
} 

由於bitWorking指出你也錯過了致電execute：

$STH = $DBH->prepare('SELECT * FROM `component`'); 
$STH->execute(); 
# setting the fetch mode 
$STH->setFetchMode(PDO::FETCH_ASSOC);