TYPO3 MySQL选择查询，可在phpMyAdmin中使用，但不适用于TYPO3

Question

If I run the code below in phpMyAdmin for my DB, then I get 17 records, but when I run it in TYPO3 6.1.4 I get all records in DB (200), why does it not work 100% in TYPO3, when it works in phpMyAdmin.

public function getKategorierne($catId){
        //print $catId;
        $query = $this->createQuery();
        $query->statement('SELECT * '.
                            'FROM sys_category_record_mm '.
                            'INNER JOIN sys_category ON ( uid = uid_local ) '.
                            'WHERE tablenames = "tx_origkentaurproducts_domain_model_design" '.
                            'AND sys_category_record_mm.uid_local '.
                            'IN ('.$catId.') '.
                            'ORDER BY uid_foreign');

        return $query->execute();

    }

Answer 1

And why all the inverted commas!?!?

$query = "
SELECT * 
  FROM sys_category_record_mm r
  JOIN sys_category c
    ON uid = uid_local 
 WHERE tablenames = 'tx_origkentaurproducts_domain_model_design' 
   AND r.uid_local IN ('$catId') 
 ORDER 
    BY uid_foreign;
";