PHP和PDO的foreach循環

Question

這個mysql更新：

 function updateOrder($id_array){
    $count = 1;
    foreach ($id_array as $id){
      $update = mysqli_query($this->connect,"UPDATE `table_name` SET `order_id` = $count WHERE id = $id");
      $count ++;  
    }
    return true;
  }

我將更改為PDO，這是我編寫的代碼，但可以工作。
但這並沒有反映在數據庫中

function update($id_array,$_table){

        $query = "UPDATE `table_name` SET `order_id` = ? WHERE id = ?";

        $stmt = $this->conn->prepare($query);  

        $count = 1;
         foreach ($id_array as $id) { 
    $stmt->execute(array(':$count' =>  $count, ':id' => $id));
      $count ++;
        }
          return true;
      }

通話功能：

$idArray    = explode(",",$_POST['ids']);<br>
$db->update($idArray);  

Answer 1

采用：

$stmt->execute(array(':count' =>  $count, ':id' => $id));

代替

$stmt->execute(array(':$count' =>  $count, ':id' => $id));

：$ count到：count