Выборка из mysql из одного столбца по нескольким параметрам

$sth = $dbh->prepare("SELECT * FROM `db` WHERE  `col` in (0,1) ORDER BY `id` DESC LIMIT 20");

$sth = $dbh->prepare("SELECT * FROM `db` WHERE  `col` in ('op1','op2') ORDER BY `id` DESC LIMIT 20");

$params = array('0', $username);
$place_holders = implode(',', array_fill(0, count($params), '?'));
$sth = $dbh->prepare("SELECT * FROM `chat` WHERE `id` > :last_id and `room` = '$room' and `private` IN  ($place_holders) ORDER BY `id` DESC LIMIT 20");
$sth->bindParam(':last_id', $last_id, PDO::PARAM_INT);
$sth->execute();

$sth = $dbh->prepare("SELECT * FROM `db` WHERE  `col` in ('op1','op2') ORDER BY `id` DESC LIMIT 20");

$sth = $dbh->prepare("SELECT * FROM `db` WHERE `col` LIKE '%op1%' AND `col` LIKE '%op2%' ORDER BY `id` DESC LIMIT 20");

$query = $db->query( "****" );
        $resource = $query->fetch(PDO::PDO_STATEMENT);

$sth = $db->prepare("SELECT `id` , `name` FROM `test` WHERE `name` IN ( 'user_a' , 'user_b' , 'user_c' ) ORDER BY `id` DESC LIMIT 20");
$sth->execute();
echo "<pre>";
var_dump($sth->fetchAll(PDO::FETCH_OBJ));
echo "</pre>";

array(3) {
  [0]=>
  object(stdClass)#4 (2) {
    ["id"]=>
    string(2) "22"
    ["name"]=>
    string(6) "user_c"
  }
  [1]=>
  object(stdClass)#5 (2) {
    ["id"]=>
    string(2) "12"
    ["name"]=>
    string(6) "user_b"
  }
  [2]=>
  object(stdClass)#6 (2) {
    ["id"]=>
    string(1) "3"
    ["name"]=>
    string(6) "user_a"
  }
}

$sth = $db->prepare("SELECT `id` , `name` FROM `test` WHERE `name` LIKE '%user_%'  ORDER BY `id` DESC LIMIT 20");
$sth->execute();
echo "<pre>";
var_dump($sth->fetchAll(PDO::FETCH_OBJ));
echo "</pre>";

array(20) {
  [0]=>
  object(stdClass)#4 (2) {
    ["id"]=>
    string(2) "52"
    ["name"]=>
    string(7) "user_77"
  }
  [1]=>
  object(stdClass)#5 (2) {
    ["id"]=>
    string(2) "51"
    ["name"]=>
    string(7) "user_76"
  }
  [2]=>
  object(stdClass)#6 (2) {
    ["id"]=>
    string(2) "50"
    ["name"]=>
    string(7) "user_97"
  }
****
[19]=>
  object(stdClass)#23 (2) {
    ["id"]=>
    string(2) "33"
    ["name"]=>
    string(7) "user_39"
  }
}

$sth = $db->prepare(); $sth->execute(); ...

$stmt = $dbh->prepare("INSERT INTO REGISTRY (name, value) VALUES (:name, :value)");
$stmt->bindParam(':name', $name);
$stmt->bindParam(':value', $value);
$name = 'one';
$value = 1;
$stmt->execute();

$query = $db->query( "SELECT `id` , `name` FROM `test` WHERE `name` IN ( 'user_a' , 'user_b' , 'user_c' ) ORDER BY `id` DESC LIMIT 20" );
$resource = $query->fetchAll(PDO::FETCH_OBJ);