Question

我一直在努力让以下代码运行，它不会返回任何内容：

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();
}

任何帮助将不胜感激。 Rgds，Stew

Answer 1

fetchAll会返回所有行，如果您想迭代结果，可以使用fetch：

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

或者如果你想坚持使用fetchAll()：

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

正如bitWorking指出的那样，你也错过了对execute的调用：

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

Answer 2

您错过了execute方法。使用fetchAll也是错误的。

请参阅Example #1 Fetch all remaining rows in a result set

fetchMode的另一个例子：

$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";
}

PDO - 从Select语句显示行

2 个答案: