为什么我的代码只返回数据库中的一行

这是我正在处理的代码，它只从数据库返回一行

    $positions =[];
        $rows= query("SELECT symbol,shares from portfolio where id=?",
        $_SESSION["id"]);
        foreach($rows as $row)
{
$stock =lookup($row["symbol"]);
if($stock!== false){
$positions =[
"symbol" =>$row["symbol"],
"nam" =>$stock["name"],
"shares" => $row["shares"],
"pric" =>$stock["price"],
"total" => $stock["price"] * $row["shares"]
];
}
}
render("portfolio.php",["ways" =>$positions,"title"=>"Portfolio"] );

查找就是函数。以下代码适用于公文包.php

<?php foreach($ways as $position =>$values) : ?>
<th>
<?= $values ?>
</th>
<?php endforeach ?>

下面是上面（最上面）代码中声明的查询函数。

 function query(/* $sql [, ... ] */)
    {
        // SQL statement
        $sql = func_get_arg(0);
        // parameters, if any
        $parameters = array_slice(func_get_args(), 1);
        // try to connect to database
        static $handle;
        if (!isset($handle))
        {
            try
            {
                // connect to database
                $handle = new PDO("mysql:dbname=" . DATABASE . ";host=" . SERVER, USERNAME, PASSWORD);
                // ensure that PDO::prepare returns false when passed invalid SQL
                $handle->setAttribute(PDO::ATTR_EMULATE_PREPARES, false); 
            }
            catch (Exception $e)
            {
                // trigger (big, orange) error
                trigger_error($e->getMessage(), E_USER_ERROR);
                exit;
            }
        }
        // prepare SQL statement
        $statement = $handle->prepare($sql);
        if ($statement === false)
        {
            // trigger (big, orange) error
            trigger_error($handle->errorInfo()[2], E_USER_ERROR);
            exit;
        }
        // execute SQL statement
        $results = $statement->execute($parameters);
        // return result set's rows, if any
        if ($results !== false)
        {
            return $statement->fetchAll(PDO::FETCH_ASSOC);
        }
        else
        {
            return false;
        }
    }