Calculating a Moving Average MySQL?

Question

Good Day,

I am using the following code to calculate the 9 Day Moving average.

SELECT SUM(close)
FROM tbl
WHERE date <= \'2002-07-05\'
AND name_id         


        

Answer 1

This query is fast:

select date, name_id,
case @i when name_id then @i:=name_id else (@i:=name_id)
and (@n:=0)
and (@a0:=0) and (@a1:=0) and (@a2:=0) and (@a3:=0) and (@a4:=0) and (@a5:=0) and (@a6:=0) and (@a7:=0) and (@a8:=0)
end as a,
case @n when 9 then @n:=9 else @n:=@n+1 end as n,
@a0:=@a1,@a1:=@a2,@a2:=@a3,@a3:=@a4,@a4:=@a5,@a5:=@a6,@a6:=@a7,@a7:=@a8,@a8:=close,
(@a0+@a1+@a2+@a3+@a4+@a5+@a6+@a7+@a8)/@n as av
from tbl,
(select @i:=0, @n:=0,
        @a0:=0, @a1:=0, @a2:=0, @a3:=0, @a4:=0, @a5:=0, @a6:=0, @a7:=0, @a8:=0) a
where name_id=2
order by name_id, date

If you need an average over 50 or 100 values, it's tedious to write, but worth the effort. The speed is close to the ordered select.