Passing variable and building an sql ejection or put the variable?

The variables below are passed into itemdetails2.php

<a href=\"itemdetails2.php?id=". $content['id'] ."&platename=".$content['platename']."\">

PHP:

In itemdetails2.php I pull the variables from the url making available through out the whole script in itemdetails2.php by:

<?php $shoename = $_GET['platename'];
 $id = (int)$_GET['id']; if( $id === 0)
 { exit('ID can only be an integer'); } ?>

PHP:

After I make it available through out the whole script in itemdetails2.php I want to build a sql injection that takes the value of the variable $shoename and put it inside the OutputRating method parameter below

<?php $ratingData = Rating::OutputRating('paul');
 if (Error::HasErrors()) 
{ echo Error::ShowErrorMessages(); Error::ClearErrors(); } 
else { echo $ratingData; } ?> 

PHP:

Notice in the parameter it says paul instead of paul I want it to contain the shoename variable value in the url.

<?php $shoename = $_GET['platename']; 
$id = (int)$_GET['id']; if( $id === 0) 
{ exit('ID can only be an integer'); } ?>
<?php $ratingData = Rating::OutputRating('$shoename');
 if (Error::HasErrors()) 
{ echo Error::ShowErrorMessages(); Error::ClearErrors(); }
 else { echo $ratingData; } ?> 

PHP:

is that correct to put $shoename variable in there just like I did in the last embed script?