1.第一种写的是数据库表的字段

QueryWrapper<User> wrapper = new QueryWrapper<>();
		wrapper.select("id","name").like("name","张三").lt("age",40);
		return userMapper.selectList(wrapper);

2.第二种对应的实体

//查询所有用户
        LambdaQueryWrapper<PhotoUser> wrapperUser = Wrappers.lambdaQuery();
        wrapperUser.select(PhotoUser::getNickname,PhotoUser::getAppellation).or().in(PhotoUser::getId,userIdList);
        List<PhotoUser> photoUsers = userService.list(wrapperUser);