php mysql how to check NULL column with php

how to check mysql NULL columns variable with php?

my rows table (example):

1 ---- james ------ italy

2 ---- joyee ------ NULL

my fetch array from table:

$rows[0] = array('name' => 'james', 'country' => 'italy');
$rows[1] = array('name' => 'joyee', 'country' => NULL);

but my problem:

how to check NULL array element:

foreach($rows as $row) {

     if ($row['country'] == NULL) echo "country is null"; // not working
     if ($row['country'] == '') echo "country is null"; // not working
     if (is_null($row['country'])) echo "country is null"; // not working
     if (empty($row['country'])) echo "country is null"; // not working
     // what is  solution? how to check null?

}

update (var_dump):

'country' => null