我不能在if语句中得到“和”和“或”一起工作

Question

I really can't get this working.

The users account type is assigned to the $_SESSION["user_type"].

You have 2 account types that can edit orders. Admins(admin) and Sub Admins(sadmin).

The "content_id" is the information displayed depending on the the page type.

What's wrong with this statement?

And yes. ob_start(); and session_start(); are running

//Disallow all users from edit orders. Except admins and Sub admins.
if ($_SESSION["user_type"] !== "admin" || $_SESSION["user_type"] !== "sadmin" && $_GET["content_id"] == "edit_order"){
  header ("location:home.php");
}

Answer 1

Here are some basics:

true  || *anything* = true
false || false      = false
false && *anything* = false
true  && true       = true

Now that we have established that, let's get to what you want.

Users who can edit your page is either admin OR sub-admin. The reverse, user who cannot edit your page, is neither admin nor sub-admin.

That gives us: User who is non-admin AND non-subadmin AND is trying to access edit page, send to home page.

if ($_SESSION["user_type"] !== "admin" && $_SESSION["user_type"] !== "sadmin" && $_GET["content_id"] == "edit_order")
{
   header ("location:home.php");
}

By the way, any reason you are using !== for checking user type, but == to check content id?