hyperlink sort database - php

Question

i want to do sorting by clicking on the hyperlinked column header...
yes i managed to do it if i put sql statement in the if condition ..
example
td> <a style="width:100px;font-family:Arial;font-size:12px;color:white" href="?run=Process">Process</a></td>
php ;
$run = $_GET['run'];
if($run=="Process")
{
$sql = "select * from audit";
}
but the problem here... i want to assign sql statement before the if condition~
when i assign
$sql = "select audit.user,audit.tarikh,activity_ref.activity from audit left join activity_ref on audit.taskID = activity_ref.idactivity_ref
where audit.user = '".$_SESSION['USER']."'";
or
$user = $_POST["searchUser"];
if($user)
{
$sql = "select audit.user,audit.tarikh,activity_ref.activity from audit left join activity_ref on audit.taskID = activity_ref.idactivity_ref
where audit.user = '$user'";
}
the if condition == process does not understand $user value / $_session['User'] value..
ive assigned them with some value at the beginning.
ive been trying for all day long.. i guess i dont understand the concept well can you help me :( ..

Answer 1

it happened because i forgot to put this code ~
if($_SERVER['QUERY_STRING'])
{
}
it should be like this
if($_SERVER['QUERY_STRING'])
{
$run = $_GET['run'];
if($run=="Process")
{
$sql = "select audit.user,audit.tarikh,activity_ref.activity from audit left join activity_ref on audit.taskID = activity_ref.idactivity_ref
where audit.user = '".$_SESSION['USER']."'";
}
}