How to print all the elements of a specific column from a table from database in custom module?
You made 4 errors:


You should use {} around table names, not ``.
print_r does not like objects Drupal uses, for testing purposes it's way better to use

while($row = $result->fetchAssoc() ){
}
$node may be already used elsewhere, it's not wise to use common names if you don't mean it.
SELECT *FROM should be SELECT * FROM (kudos for Clive)