Inner join and PDO - php

Question

I have a problem with INNER JOIN and PDO. My query is working just fine when not using INNER JOIN. When adding INNER JOIN to the query nothing shows.
Is this a way to go or am I completely wrong?
Any suggestions?
public function search($searchterm)
{
$query = $this->db->prepare("
SELECT
ad.id AS idet,
ad.lid,
ad.firstname AS firstnamer,
ad.surname AS surnamer,
ad.socialnr AS socialnumber,
ba.class AS classes
FROM `everybody` ad
INNER JOIN `students` ba
ON idet = ba.id
WHERE (`firstname` LIKE :search OR `surname` LIKE :search OR `classes` LIKE :search)");
$searchterm = '%' . $searchterm . '%';
$query->bindParam(':search', $searchterm, PDO::PARAM_STR);
$query->execute();
while($row = $query->fetch(PDO::FETCH_ASSOC)) {
echo $row['idet']. ' : '. $row['firstnamer']. ' '. $row['surnamer']. ' - '. $row['socialnumber']. ' Class: '. $row['classes']. '<br />';
}
}

Answer 1

You can't use a column alias in ON or WHERE. It should be
ON ad.id = ba.id
In case there are other SQL errors, you should enable PDO exceptions:
$this->db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

Answer 2

Try by changing
INNER JOIN `students` ba
ON ad.id = ba.id
/*^^^^*/
WHERE (ad.firstname LIKE :search OR ad.surname LIKE :search OR ad.class LIKE :search)");
/*^^*/ /*^^*/ /*^^*/

Answer 3

Thank you all for your help.
Yes I have enabled exceptions for PDO errors. No error are registered. I have tried your suggestions as posted above. Nothing works.
When not using INNER JOIN, this code works like a charm:
public function search($searchterm)
{
$query = $this->db->prepare("
SELECT
id,
lid,
firstname,
surname,
socialnr
FROM `everybody`
WHERE (`firstname` LIKE :search OR `surname` LIKE :search)");
$searchterm = '%' . $searchterm . '%';
$query->bindParam(':search', $searchterm, PDO::PARAM_STR);
$query->execute();
while($row = $query->fetch(PDO::FETCH_ASSOC)) {
echo $row['id']. ' : '. $row['firstname']. ' '. $row['surname']. ' - '. $row['socialnr']. '<br />';
}
}
The difference between the code in my first post and this one, is the absence of INNER JOIN. I hope it will help any one to help me to understand why.
Is this the right approach? Do I need to rethink this and rewrite my function? Please advice in any direction to help me on the right track. You are most helpful. Thanks.