php - PDO结果为空但查询通过MySQL返回数据

Question

我有这个代码:

$sql = "SELECT Username,Level FROM users WHERE Username = :username";
print $sql;
$sth = $dbh->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY));
$sth->execute(array(':username' => $username));
$data = $sth->fetchAll();
print_r($data);

没有打印任何数据，但是当我将 print $sql 的结果复制到 MySQL 并运行查询(用该列中的值替换 :username)时，我得到了结果。

为什么没有检索到数据？

编辑:$username 来自表单，所以我这样做:

$username = $_POST['username']; // print $username shows entered value

我的连接不是问题，我调用一个函数根据参数返回正确的连接

$debh = getConnection('read'); // creates connection with user with select privs

getConnection 内部:

    case "read":
        $connection = new PDO('mysql:host=' . $host . ';dbname=' . $dbName . '', "$readUser", "$readUserPassword");
        break;

Answer 1

这对我有用:

<?php
$username = 'user@email.com';
$dbh = new PDO('mysql:host=localhost;dbname=stackoverflow;charset=utf8', 'user', 'password');
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$dbh->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
$sql = "SELECT Username,Level FROM users WHERE Username = :username";
print $sql;
$sth = $dbh->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY));
$sth->execute(array(':username' => $username));
$data = $sth->fetchAll();
print_r($data);

• 确保更改数据库凭据
• user@email.com 是我数据库中的用户