Q&A about the site for mechanics and DIY enthusiast owners of cars, trucks, and motorcycles
select _year, _month, (a - b + 0.0) / a * 100 from ( select _year, _month, _count as b, lag(_count) over (order by _year, _month) as a from ( select year(CreationDate) as _year, month(CreationDate) as _month, count(id) as _count from Posts group by year(CreationDate), month(CreationDate) ) q ) q2