Question

我有以下功能

public function checkLogin($username, $password){

    $select_query = $this->connect()->prepare("SELECT `username` , `password` FROM `users` 
            WHERE `username` = :username AND `password` = :password");
$select_query->bindParam(':username', $username);
$select_query->bindParam(':password', $password);
try{
        $select_query->execute(); 
    } catch(PDOException $ex) {
        echo "An Error occured while checking for username!\n"; //user friendly message
        logger($ex->getMessage());
    }
    return ($select_query->fetchColumn() > 0) ? true : false;
}

当$ username是test并且$ password是password时，alwasy什么都不返回，当我从phpMyAdmin运行sql时，它会给出正确的结果。这是我在phpMyAdmin上运行的

SELECT  `username` ,  `password` 
FROM  `users` 
WHERE  `username` =  'test'
AND  `password` =  'password'

它返回1个正确的用户。

Answer 1

尝试指定参数的类型：

$select_query->bindParam(':username', $username, PDO::PARAM_STR);
$select_query->bindParam(':password', $password, PDO::PARAM_STR);

Answer 2

此外，您可以使用bindValue代替bindParam

$select_query->bindValue(':username', $username);
$select_query->bindValue(':password', $password);

Answer 3

再看一下你的sql语句：

"SELECT `username`, `password`
FROM `users` 
WHERE `username` = :username AND `password` = :password"

因为您正在搜索字符串数据类型，所以需要将：username和：password slugs包装在单引号中。试试这个，它应该可以解决问题。

PDO选择查询不返回任何内容

3 个答案: