com_sportsmanager/scripts/migrate_add_reminder_fields.php

<?php
// Migration script to add reminder fields to #__sportsmanager_turnier
// Usage: php scripts/migrate_add_reminder_fields.php

use Joomla\CMS\Factory;

if (!defined('_JEXEC')) {
    define('_JEXEC', 1);
    define('JPATH_BASE', dirname(__DIR__, 6));
    require_once JPATH_BASE . '/includes/defines.php';
    require_once JPATH_BASE . '/includes/framework.php';
}

function addReminderFieldsToTurnierTable()
{
    $db = Factory::getDbo();
    $columns = [
        'reminder_24h_sent',
        'reminder_3d_sent',
        'reminder_7d_sent',
    ];
    // Check if columns already exist
    $db->setQuery("SHOW COLUMNS FROM #__sportsmanager_turnier");
    $existing = array_column($db->loadAssocList(), 'Field');
    $alter = [];
    if (!in_array('reminder_24h_sent', $existing)) {
        $alter[] = 'ADD COLUMN `reminder_24h_sent` DATETIME DEFAULT NULL';
    }
    if (!in_array('reminder_3d_sent', $existing)) {
        $alter[] = 'ADD COLUMN `reminder_3d_sent` DATETIME DEFAULT NULL';
    }
    if (!in_array('reminder_7d_sent', $existing)) {
        $alter[] = 'ADD COLUMN `reminder_7d_sent` DATETIME DEFAULT NULL';
    }
    if ($alter) {
        $query = 'ALTER TABLE #__sportsmanager_turnier ' . implode(', ', $alter);
        $db->setQuery($query);
        $db->execute();
        echo "Migration successful: reminder fields added.\n";
    } else {
        echo "Migration skipped: fields already exist.\n";
    }
}

addReminderFieldsToTurnierTable();