PHP: array becomes empty after foreach() loop

Question

I have this query

$categories = $dbh->query(" SELECT * FROM categories ORDER BY name ASC ");

and I need to loop two times over this array.

foreach($categories as $category) {
    dd($category);
}
echo '---------------';
foreach($categories as $category) {
    dd($category);
}

This code returns

stdClass Object
(
    [id] => 24
    [name] => granchi
    [slug] => granchi
)
stdClass Object
(
    [id] => 26
    [name] => molluschi
    [slug] => molluschi
)
stdClass Object
(
    [id] => 25
    [name] => pesci
    [slug] => pesci
)
---------------

In the second loop the array becomes empty. I have found a similar question, Two While Loops, Second Returns Empty Array? , but I didn't find a similar solution for PDO.

Without querying two times creating two identical arrays, how do I loop through them twice ?

And I do not understand why it empties after the first loop.

I solved it already, I was missing ->fetchAll(). dd() is just a helper function, <pre> print_r($obj) </pre> — C. Ovidiu
– C. Ovidiu, Commented Jul 21, 2014 at 15:47

Ozan Kurt · Accepted Answer · 2014-07-21 14:17:15Z

4

You must first fetch the result of a query into an array.

Mysqli:

<?php

$db = new mysqli('localhost', 'root', '', 'test');

if($db->connect_errno > 0){
    die('Unable to connect to database [' . $db->connect_error . ']');
}

$sql = " SELECT * FROM categories ORDER BY name ASC ";

if(!$result = $db->query($sql)){
    die('There was an error running the query [' . $db->error . ']');
}

while($row = $result->fetch_assoc()){
    echo $row['**column name**'] . '<br />';
}

?>

PDO:

<?php

$db = new PDO('mysql:host=localhost;dbname=test;charset=utf8', 'root', '');

$sql = "SELECT * FROM categories ORDER BY name ASC ";

try {
    $stmt = $db->query($sql);
} catch(PDOException $ex) {
    echo "An Error occured!";
}

$result = $stmt->fetch(PDO::FETCH_ASSOC);

foreach($result as $key => $val)
    {
    echo $key.' - '.$val.'<br />';
    }

?>

edited Jul 21, 2014 at 14:17

answered Jul 21, 2014 at 14:09

Ozan Kurt

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1 Comment

C. Ovidiu Over a year ago

Oh, I can't believe I forgot to add ->fetchAll(). Without it still loops one time. Thanks and sorry

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