mince/database/2023_08_16_161818_existing_structure.php

<?php
use Index\Db\DbConnection;
use Index\Db\Migration\DbMigration;

final class ExistingStructure_20230816_161818 implements DbMigration {
    public function migrate(DbConnection $conn): void {
        $hasWhiteList2020 = false;
        $hasWhiteList2022 = false;

        // check if the old tables exist
        $tables = $conn->query('SHOW TABLES');
        while($tables->next()) {
            $tableName = $tables->getString(0);
            if($tableName === 'whitelist')
                $hasWhiteList2020 = true;
            elseif($tableName === 'whitelist_2022')
                $hasWhiteList2022 = true;
            if($hasWhiteList2020 && $hasWhiteList2022)
                break;
        }

        if(!$hasWhiteList2020)
            $conn->execute('
                CREATE TABLE whitelist (
                    flashii_id         INT(10) UNSIGNED NOT NULL,
                    minecraft_username VARCHAR(255)     NOT NULL COLLATE "utf8mb4_unicode_ci",
                    whitelist_added    TIMESTAMP        NOT NULL DEFAULT current_timestamp(),
                    UNIQUE KEY whitelist_unique (flashii_id, minecraft_username),
                    KEY whitelist_flashii_key   (flashii_id),
                    KEY whitelist_minecraft_key (minecraft_username)
                ) ENGINE=InnoDB COLLATE="latin1_swedish_ci";
            ');

        if(!$hasWhiteList2022)
            $conn->execute('
                CREATE TABLE whitelist_2022 (
                    flashii_id         INT(10) UNSIGNED NOT NULL,
                    minecraft_username VARCHAR(255)     NOT NULL COLLATE "utf8mb4_unicode_ci",
                    whitelist_added    TIMESTAMP        NOT NULL DEFAULT current_timestamp(),
                    UNIQUE KEY whitelist_2022_unique (flashii_id, minecraft_username),
                    KEY whitelist_2022_flashii_key   (flashii_id),
                    KEY whitelist_2022_minecraft_key (minecraft_username)
                ) ENGINE=InnoDB COLLATE="latin1_swedish_ci";
            ');
    }
}