PHP MySQL Heredoc语法-我应将mysqli_real_escape_string（）放在哪里？

Question

我不确定将mysqli_real_escape_string()放在我当前的MySQL MySQL代码中的位置。

我有URl http://www.example.com/abc-vs-def-vs-ghi/，但是我知道它可以暴露于http://www.example.com/abc:_?!$123-vs-1312+'。

我的代码是：

// This I got from my URL - be aware of SQLi!!!
$uri_segments="abc-vs-def-vs-ghi";

// array to get abc def ghi
$compare = explode('-vs-',$uri_segments[0]);

// db connection
$con = mysqli_connect("localhost","user","password","database");

// array for ID's by url segment abc, def, ghi for later
$device_models = array();

// loop array abc def ghi to get the ID from database
foreach ($compare as $model) {

// sql - where to put mysqli_real_escape_string()?
$sql = <<<SQL
SELECT model_id
FROM device_model
WHERE device_model.model_seo_url = '${model}'
SQL;

// get the id for abc, def, ghi
$result = mysqli_query($con, $sql) or die(mysqli_error($con));

  while($row = mysqli_fetch_assoc($result)){
    $device_model_id = $row['model_id'];
    // add id to array
    $device_models[] = $device_model_id;
  }

}

// close connection
mysqli_close($con);

// id 1,2,3
$var = implode (",", $device_models);
echo $var; // 1,2,3

我应该将ins insie $ sql变量放入'mysqli_real_escape_string(${model})'吗？

还是'${mysqli_real_escape_string(model)}'？

我无法正常工作。

也许在foreach（）循环内？

谢谢您的帮助！