If Statement with Empty _Get - php

Question

I am busy learning PHP. However doing a small website with PHP where I control the Variables passed, I am stuck at a If statement issue.
Every internal page link I have passes a variable to control the content I pull from a database. even links from other internal pages to my Index.php page. The thing is the index.php page gives errors because there is a empty _Get issue when you enter the saite from external link. There are four pages. all other pages work with no errors but loading index page gives error.
My code:
$Section = $_GET['SID'];
if ( $Section == "HOME" ) {
$SectionTitle = 'Start';
$SectionID = 'HOME';
}
if ( $Section == "BDIR" ) {
$SectionTitle = 'Directory';
$SectionID = 'BDIR';
}
if ( $Section == "ACOM" ) {
$SectionTitle = 'Accommodation';
$SectionID = 'ACOM';
}
if ( $Section == "REST" ) {
$SectionTitle = 'Restaurants';
$SectionID = 'REST';
}
What I need to achieve is when there is an empty _Get its must assign the same value as the Home (First If) Values.
I have tried
if (!empty($_GET)) {
$SectionTitle = 'Start';
$SectionID = 'HOME';
}
and a few other variations with no luck.
But I think I am out of my league, as I wonder, should some if my statements not be within(under) other if statements here?

Answer 1

$Section = !isset($_GET['SID']) || empty($_GET['SID']) ? 'HOME' : $_GET['SID'];
switch($Section) {
case "BDIR":
$SectionTitle = 'Directory';
$SectionID = 'BDIR';
break;
case "ACOM"
$SectionTitle = 'Accommodation';
$SectionID = 'ACOM';
break;
case "REST":
$SectionTitle = 'Restaurants';
$SectionID = 'REST';
break;
case "HOME":
default:
$SectionTitle = 'Start';
$SectionID = 'HOME';
break;
}

Answer 2

In order not to write many similar if-statements i'd rather add an array and check it by key presence.
Then define default SectionTitle and SectionID like this:
<?php
$SectionTitle = 'Start';
$SectionID = 'HOME';
$sections = [
'BDIR' => 'Directory',
'ACOM' => 'Accommodation',
'REST' => 'Restaurants'
];
if (!empty($_GET['SID']) && array_key_exists($_GET['SID'], $sections)) {
$SectionTitle = $sections[$_GET['SID']];
$SectionID = $_GET['SID'];
}

Answer 3

May be this will help you. try this code.
if($_GET)
{
$Section = $_GET['SID'];
if ( $Section == "HOME" ) {
$SectionTitle = 'Start';
$SectionID = 'HOME';
}
if ( $Section == "BDIR" ) {
$SectionTitle = 'Directory';
$SectionID = 'BDIR';
}
if ( $Section == "ACOM" ) {
$SectionTitle = 'Accommodation';
$SectionID = 'ACOM';
}
if ( $Section == "REST" ) {
$SectionTitle = 'Restaurants';
$SectionID = 'REST';
}
}