Is there a way to fetch associative array grouped by the values of a specified column with PDO?

Question

For example, let\'s use some simple data set

+---------+------+------+------------+
| name    | age  | sex  | position   |
+---------+------+------+---------         


        

Answer 1

We can make Charles' solution a little nicer by extending the statement class instead:

class MyPdo extends PDO {
    function __construct($host, $database_name, $username, $password, $options=array()) {
        $options = self::merge(array(
            PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
            PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
            PDO::ATTR_STATEMENT_CLASS => array('PdoPlusStatement', array()),
            PDO::ATTR_EMULATE_PREPARES => true,
            PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES utf8',
        ), $options);
        $dsn = "mysql:host=$host;dbname=$database_name;charset=utf8";
        parent::__construct($dsn, $username, $password, $options);
    }
}

class PdoPlusStatement extends PDOStatement {
    protected function __construct() {}

    /**
     * @param array|mixed $input_parameters An array of values with as many elements as there are bound parameters in the SQL statement being executed, or one or more non-array arguments to be matched with sequential parameter markers.
     * @throws PDOException
     * @return PdoPlusStatement
     */
    public function execute($input_parameters=null) {
        $args = func_get_args();
        $argc = func_num_args();
        if($argc===0) {
            parent::execute();
        } else {
            if($argc===1 && is_array($args[0])) {
                $args = $args[0];
            }
            parent::execute($args);
        }
        return $this;
    }

    /**
     * Returns an array containing all of the remaining rows in the result set
     * @return array An associative array using the first column as the key, and the remainder as associative values
     */
    public function fetchKeyAssoc() {
        return array_map('reset', $this->fetchAll(PDO::FETCH_GROUP|PDO::FETCH_ASSOC));
    }
}

Usage:

$users = $pcs->query("SELECT name, user_id, discipline_id FROM wx_user")->fetchKeyAssoc();