Question

For a “submit” input item:

name="remove['.$username.']['.$event_id.']" 

if (isset($_POST[remove])) {
    foreach ($_POST[remove] as $username => $event_obj) {
        foreach ($event_obj as $event_id => $obj) {
            delete .... WHERE event_id='$event_id' AND username='$username'");
        }
    }
}

Is there a shorter way to get the associative keys used in an array that has one item?

Answer 1

Use array_keys() to get all the event_id values at once. This will only require one query per user name, too.

if( isset( $_POST['remove'])) {
    foreach( $_POST['remove'] as $username => $event_obj) {
        $event_ids = array_map( 'intval', array_keys( $event_obj));
        $sql = 'DELETE FROM mytable 
                    WHERE event_id IN ( ' . implode( ' OR ', $event_ids) . ' ) 
                        AND username = "' . $username  . '"'; // Sanitize $username
    }
}