PHP array_push overwriting the pushed data

Question

I seeing a rare behavior of the array_push php function. It's like when I'm looping through the result rows of the query and pushing the complete array of data into a 'parent' array ($rdo), the values are beeing modified with the ones of the last row added.

This is my code:

$rdo = array();

if($sentencia = $general_con->prepare("SELECT monthly_price, name FROM subscription_plan WHERE deleted=0"))
{
    $sentencia->execute();

    $sentencia->store_result();
    $num_of_rows = $sentencia->num_rows;

    $sentencia->bind_result($row['monthly_price'], $row['name']);

    while($sentencia->fetch())
    {
        array_push($rdo, $row);

        echo print_r($rdo,1).'<br/><br/>';
    }
    $sentencia->close();
    die();
}

And this is the result:

Did you mean to write while($row = $sentencia->fetch())? Because right now you're not changing $row anywhere. — Tim Roberts
– Tim Roberts, Commented Jan 26, 2022 at 21:20
I think this is due to the way bind_results() binds to references. I'm not sure why this is happening, since array_push() should make a copy of $row. — Barmar
– Barmar, Commented Jan 26, 2022 at 21:22
@TimRoberts like Barmar commented, I'm binding the results into the $row array with bind_results, and then in the while looping throgh the result length to access every row — ajzbrun
– ajzbrun, Commented Jan 26, 2022 at 21:24

Barmar · Accepted Answer · 2022-01-26 21:25:28Z

1

It looks like this is an artifact of the way bind_result() uses references to the array elements. When you push $row onto $rdo, this is updating all those array elements.

I recommend you move away from using bind_result() and use fetch_assoc().

if($sentencia = $general_con->prepare("SELECT monthly_price, name FROM subscription_plan WHERE deleted=0"))
{
    $sentencia->execute();

    $result = $sentencia->get_result();
    
    while($row = $result->fetch_assoc())
    {
        array_push($rdo, $row);
        echo print_r($rdo,1).'<br/><br/>';
    }
    $sentencia->close();
    die();
}

answered Jan 26, 2022 at 21:25

Barmar

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1 Comment

ajzbrun Over a year ago

Excellent, this works! I don't know what is the issue with the other way, but this solution works just fine :)

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