display unique values from MYSQL PHP

Question

I am trying to get the isbn number of a book from a database, but with my command it is giving me an associative array.

How do I get it to return just the isbn number in the array.

Code:

function view_all_names($db)
{
$query = "SELECT  isbn from books";

$statement = $db->prepare($query);
$statement->execute();
$result = $statement->fetchAll();
$statement->closeCursor();
return $result;      

}

Answer 1

您应该只使用isbn数字，将mysql_fetch_assoc（）与while循环一起使用。

Answer 2

If $db is a PDO object you can use

$result = $statement->fetchAll(PDO::FETCH_COLUMN);

PDOStatement::fetchAll