我正在使用Docker运行我的旧WordPress项目。在Docker上迁移后，我得到这个错误：

Fatal error: Uncaught Error: Call to undefined function mysql_connect() in
/var/www/html/wp-includes/wp-db.php:1570 Stack trace: 
#0 /var/www/html/wp-includes/wp-db.php(658): wpdb->db_connect() 
#1 /var/www/html/wp-includes/load.php(404): wpdb->__construct('wordpress_user', 'secret', 'wordpress_acade...', 'academy-mysql:3...') 
#2 /var/www/html/wp-settings.php(106): require_wp_db() 
#3 /var/www/html/wp-config.php(122): require_once('/var/www/html/w...') 
#4 /var/www/html/wp-load.php(37): require_once('/var/www/html/w...') 
#5 /var/www/html/wp-blog-header.php(13): require_once('/var/www/html/w...') 
#6 /var/www/html/index.php(17): require('/var/www/html/w...') 
#7 {main} thrown in /var/www/html/wp-includes/wp-db.php on line 1570

我尝试了以下方法：- 添加MySQL扩展到Dockerfile -删除插件-更改主题但没有成功。