问题描述
我最近开始使用 PDO,之前我只使用 MySQL.现在我正在尝试从数据库中获取所有数据.
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.'); }
但它没有显示任何用户,只是一个空白页面.
But it is not showing any users, just a blank page.
推荐答案
PDO 方法 fetchAll() 返回一个数组/结果集,您需要将其分配给一个变量,然后使用/迭代该变量:
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,您似乎没有调用 execute() 方法需要在之后你准备语句但之前你实际获取数据:
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(); ...