php - 没有从 Mysqli 获取行

Question

我正在使用mysqli来获取行，但它没有给我行，并且查询中没有错误。

$query="select * from members where useremail='$user_email' and password='$password'";
$result=$db->query($query);
$row = $db->fetch_array($result);
echo $row['id'];

我的查询功能

function query($query){
        $result=mysqli_query($this->conn, $query);
        if(!$result){
            echo $this->err_msg = mysqli_error($this->conn);
            return false;
        }else{
            return $result;
        }
}

我的fetch_array函数

function fetch_array($result){
    return mysqli_fetch_array($result);
}

如何使用 mysqli 获取 Row？

Answer 1

更改原始代码以反射(reflect)使用 mysqli 的绑定(bind)参数，这更安全并且应该可以工作

$query="select * from members where useremail='$user_email' and password='$password'";
    $result=$db->query($query);
    $row = $db->fetch_array($result);
    echo $row['id'];

使用 mysqli 准备好的语句绑定(bind)参数

$query="select id from members where useremail=? and password=?";   // Don't use select *, select each column, ? are placeholders for your bind variables
$stmt = $connection->prepare($query);
if($stmt){
  $stmt->bind_param("ss",$user_email,$password);   // Bind in your variables, s is for string, i is for integers
  $stmt->execute();  
  $stmt->bind_result($id);  // bind the result to these variables, in the order you select
  $stmt->store_result();   // Store if large result set, can throw error if server is setup to not handle more than x data
  $stmt->fetch();
  $stmt->close();
  }
echo $id;  // this would be same as $row['id'], $id now holds for example 5. 

如果您选择多个内容，例如“SELECT id,name FROM...”，那么当您bind_result(..)时，只需将它们绑定(bind)在那里即可。 $stmt->bind_result($id,$name);

现在 $id 和 $name 保存与您的查询匹配的行的列数据。如果有多行匹配，您可以代替 $stmt->fetch()

while($stmt->fetch()){    // just like while($row = $result->fetch_assoc()){}
   echo $id;
   echo $name
}