I'm stucked in a MySQL problem that I was not able to find a solution yet. I have the following query that brings to me the month-year and the number new users of each period in my platform:

```
select  
    u.period ,
    u.count_new as new_users
from 
(select DATE_FORMAT(u.registration_date,'%Y-%m') as period, count(distinct u.id) as count_new from users u group by DATE_FORMAT(u.registration_date,'%Y-%m')) u
order by period desc;

```

The result is the table:

```
period,new_users
2016-10,103699
2016-09,149001
2016-08,169841
2016-07,150672
2016-06,148920
2016-05,160206
2016-04,147715
2016-03,173394
2016-02,157743
2016-01,173013

```

So, I need to calculate for each month-year the difference between the period and the last month-year. I need a result table like this:

```
period,new_users
2016-10,calculate(103699 - 149001)
2016-09,calculate(149001- 169841)
2016-08,calculate(169841- 150672)
2016-07,So on...
2016-06,...
2016-05,...
2016-04,...
2016-03,...
2016-02,...
2016-01,...

```

Any ideas: =/

Thankss