本文介紹了PDO 從數據庫中獲取數據的處理方法，對大家解決問題具有一定的參考價值，需要的朋友們下面隨著小編來一起學習吧！
問題描述
我最近開始使用 PDO，之前我只使用 MySQL.現在我正在嘗試從數據庫中獲取所有數據.
I started using PDO recently, earlier I was using just MySQL. Now I am trying to get all data from database.
$getUsers = $DBH->prepare("SELECT * FROM users ORDER BY id ASC");
$getUsers->fetchAll();
if(count($getUsers) > 0){
while($user = $getUsers->fetch()){
echo $user['username']."<br/>";
}
}else{
error('No users.');
}
但它沒有顯示任何用戶，只是一個空白頁面.
But it is not showing any users, just a blank page.
推薦答案
PDO 方法 fetchAll() 返回一個數組/結果集，您需要將其分配給一個變量，然后使用/迭代該變量:
The PDO method fetchAll() returns an array/result-set, which you need to assign to a variable and then use/iterate through that variable:
$users = $getUsers->fetchAll();
foreach ($users as $user) {
echo $user['username'] . '<br />';
}
更新(缺少execute())
此外，您似乎沒有調用 execute() 方法需要在之后你準備語句但之前你實際獲取數據:
UPDATE (missing execute())
Also, it appears you aren't calling the execute() method which needs to happen after you prepare the statement but before you actually fetch the data:
$getUsers = $DBH->prepare("SELECT * FROM users ORDER BY id ASC");
$getUsers->execute();
$users = $getUsers->fetchAll();
...
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