为什么我得到org.json.JSONException:当我更改查询时字符0的输入结束?

I have my php file starting with

if (isset($_POST['uzip']))
{
$uzip = $_POST['uzip'];

With Below I dont get a response

 $result = mysqli_query($con,"SELECT CAT_ID, CAT_NAME, B_ID, B_NAME, B_EMAIL, B_ADDR, B_ZIP FROM Business INNER JOIN Categories ON Business.BCAT_ID = Categories.CAT_ID , Users WHERE Users.U_ZIP = Business.B_ZIP AND User.U_ZIP='".$uzip."'") or die(mysql_error());  

Below returns a response

$result = mysqli_query($con,"SELECT CAT_ID, CAT_NAME, B_ID, B_NAME, B_EMAIL, B_ADDR, B_ZIP FROM Categories INNER JOIN Business ON BCAT_ID = CAT_ID") or die(mysql_error());

How can I resolve this? is it the post parameter inside the WHERE clause?