php - Stmt 不工作

Question

我已经准备好阅读所有其他主题，但没有找到解决方案。这是我的代码

    $DevolverUser     =  $_SESSION['DevolverUser'];
    $DevolverPaswword =  $_SESSION['DevolverPaswword'];

    $query = " select puededevolver   ".
        "   from b_usuarios  ".
        "   where codpais = ? ".
        "   and usuario   = 'usuario' ".
        "   and PASSWORD = PASSWORD('password')";

    $stmt = $con ->prepare($query);
    $stmt->bind_param("s", $pais );         
    $stmt->execute();
    $stmt->bind_result($dato);

    while($stmt->fetch()){
        echo  $dato;
    }

如果我更改为

    $DevolverUser     =  $_SESSION['DevolverUser'];
    $DevolverPaswword =  $_SESSION['DevolverPaswword'];

    $query = " select puededevolver   ".
        "   from b_usuarios  ".
        "   where codpais = ? ".
        "   and usuario   = ? ".
        "   and PASSWORD = PASSWORD(?)";

    $stmt = $con ->prepare($query);
    $stmt->bind_param("sss", $pais, $DevolverUser, $DevolverPaswword  );            
    $stmt->execute();
    $stmt->bind_result($dato);

    while($stmt->fetch()){
           echo $dato;
    }

它不起作用，如果我特征只是绑定(bind)用户或只有密码不起作用，则只能使用 $pais。我已经准备好检查我的所有变量都是字符串。我不知道还需要检查什么，请帮忙。

Answer 1

编辑:我的错，我假设您正在使用PDO - 相反，您似乎使用mysqli。

这不是$stmt->bind_param()，而是$stmt->bindParam()；据我所知，像 $stmt->bind_result() 这样的东西根本不存在。我还想知道您希望在 SQL 中使用 PASSWORD(...) 实现什么目的。到目前为止我已经修复了所有我能修复的内容:

$DevolverUser     =  $_SESSION['DevolverUser'];
$DevolverPaswword =  $_SESSION['DevolverPaswword'];

$query = " select puededevolver   ".
    "   from b_usuarios  ".
    "   where codpais = :codpais ".
    "   and usuario   = :usuario ".
    "   and PASSWORD = :password ";

$stmt = $con->prepare($query);
$stmt->bindParam(":codpais", $pais);        
$stmt->bindParam(":usuario", $DevolverUser);        
$stmt->bindParam(":password", $DevolverPaswword);        
$stmt->execute();

while($row = $stmt->fetch()){
       echo $row["puededevolver"];
}