$_GET['name'] = "Peter";
$queryText = "field = $_GET['name']";

echo $queryText;

$_GET['name'] = "Peter";
$queryText = "field = '" . $_GET['name'] . "'";

echo $queryText;

$_GET['name'] = "Peter";
$queryText = "field = $_GET[name]";

echo $queryText;

$_GET['name'] = "Peter";
$queryText = "field = " . $_GET['name'];

echo $queryText;

$_GET['name'] = "Peter";
$queryText = sprintf("field = %s", $_GET['name']);

echo $queryText;

$_GET['name'] = "Peter";
$queryText = "field = {$_GET['name']}";

echo $queryText;

foreach($_GET as $key => $value) {
   $queryText = "$key = $value";
   echo $queryText;
}

$_GET['name'] = "Peter";
$queryText = "field = {$_GET['name']}";

echo $queryText;

$_GET['name'] = "Peter";
$queryText = "field = ".$_GET['name'];

echo $queryText;

$_GET['name'] = "Peter";
$queryText = "field = $_GET[name]";

echo $queryText;