相关疑难解决方法(0)

我正在尝试了解MySQL存储过程,我想检查用户登录凭据是否有效,如果是,请更新用户在线状态:

-- DROP PROCEDURE IF EXISTS checkUser;
DELIMITER //
CREATE PROCEDURE checkUser(IN in_email VARCHAR(80), IN in_password VARCHAR(50))
BEGIN
    SELECT id, name FROM users WHERE email = in_email AND password = in_password LIMIT 1;
    -- If result is 1, UPDATE users SET online = 1 WHERE id = "result_id";
END //
DELIMITER ;

如何根据结果集行数== 1或id IS NOT NULL创建此if语句？