PHP: both if and else statements are fired when I use post - php

Question

when I use $_POST, both the if and else statements are executed. But the weird thing is that only the foreach loop is executed and "Flag is 0" is printed to the screen. If I replace $Flag = 1 with $Flag = 0, in the else statement, the loop does not get executed. When I replace "isset($_POST['Back'])" with "1", again the loop does not execute and all is well. So how come both my else and my if statement execute when I use $_POST? Thank you for any input
File #1
$Flag = 0;
if (isset($_POST['Back']))
{ echo "Flag is 0";
$Value = sqlsrv_fetch_array(sqlsrv_query($dbhandle,'SELECT MAX([Protocol Branch]) FROM Import_Trial_Information'),SQLSRV_FETCH_NUMERIC);
$Value = $Value[0];
}
else {$Flag = 1; echo "Flag is 1"; }
if ($Flag)
{
foreach ($Database_Tables AS $Delete)
{
$Query = 'DELETE FROM Import_' . $Delete;
sqlsrv_query($dbhandle,$Query);
if ($Delete == 'Paper_Information') {$Protocol = array('','');}
else {$Protocol = array(',[Protocol Branch]',',1');}
$Query = 'INSERT INTO Import_' . $Delete . '([Paper ID]' . $Protocol[0] . ') VALUES (' . (string)$ID . $Protocol[1] .')';
sqlsrv_query($dbhandle,$Query);
}
$Value = 1;
}
File #2
<div id = "Back_Button">
<form action="Import_Article_Advanced.php" method = "POST"><button name = "Back" ID = "Back" Value = "Back">Return to Previous Page</button></form>
</div>

Answer 1

try this
if (isset($_POST['Back']) OR !empty($_POST['Back']) OR $_POST['Back']!="" )
{ echo "Flag is 0";
$Value = sqlsrv_fetch_array(sqlsrv_query($dbhandle,'SELECT MAX([Protocol Branch]) FROM Import_Trial_Information'),SQLSRV_FETCH_NUMERIC);
$Value = $Value[0];
}
else {$Flag = 1; echo "Flag is 1"; }