警告：非法字符串偏移：php

Question

我正在接受php交战

Warning: Illegal string offset 'item_id' in

尝试执行此代码

<?php 
error_reporting(0);
include ('includes/db.inc.php');
include ('includes/items.inc.php');

include ('header.php');
 $user_id=$_SESSION['user_id'];


   $sqll= "SELECT 'transcription.item_id' FROM transcription left JOIN items ON 'items.item_id' = 'transcription.item_tra_id';" ;
   $resultt= mysqli_query($conn,$sqll);
   $resultts= mysqli_num_rows($resultt);
   //echo $results; 
   $rers = mysqli_fetch_assoc($resultt);

   foreach ($rers as $rerss) {
    echo $rerss['item_id'] ;
   } 
   ?>

我正在搜索一个发现我需要将数组键包装在引号中，而这正是我所做的但仍然是同一个问题，我也不知道我的SQL语句是否正确。