大佬求助，mongo 分组，统计出总的记录数

聚合分页需要总记录数来返回页数，现在不知道怎么获取总的记录数了。

select count(*) from (
select sampleId,app,account,nickName
from sampleOppoAccounts where app='微信' and (account like '%a%' or nickName like '%b%') GROUP BY sampleId,app,account,nickName
);

https://blog.csdn.net/zhuchunyan_aijia/article/details/86656787