Question

如何将下面php语句中的device_token字段设置为名为$token的变量？

result = query("SELECT device_token, IdPhoto, IdUser FROM photos ORDER BY IdPhoto DESC LIMIT 1") ;

基于w3schools的SQL文档：The WHERE clause is used to extract only those records that fulfill a specified criterion.如何在上面的代码中使用它？

http://www.w3schools.com/sql/sql_where.asp

Answer 1

要获取特定令牌，您需要WHERE子句和特定userid。

$id = 1; //You may get this from a form/session you created for login user    
$dbh = new PDO('mysql:host=localhost;dbname=dbname', 'root', 'password');    
$result = $dbh->query("SELECT device_token, IdPhoto, IdUser 
                       FROM photos WHERE IdUser='$id' 
                       ORDER BY IdPhoto DESC LIMIT 1");
$devicetoken = $result->fetch(PDO::FETCH_ASSOC);

echo $devicetoken['device_token'];

但是，如果您不需要特定令牌并希望退回所有令牌，则不需要WHERE子句和LIMIT。但是，LIMIT为您提供了更改语句将返回的行数的选项。

$result = $dbh->query("SELECT device_token, IdPhoto, IdUser 
                       FROM photos
                       ORDER BY IdPhoto DESC");
$token = $result->fetch(PDO::FETCH_ASSOC);//store the device token here in $token

现在devicetoken包含所有device_token的数组。你可以使用foreach循环和while：

访问它们中的每一个

 foreach($token as $key=>$val){
      echo $val.'<br>';
 }

将值设置为变量

1 个答案: