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

Use something like

SELECT 
  sum(close) as sum,
  avg(close) as average
FROM (
    SELECT 
      (close)
    FROM 
      tbl
    WHERE 
      date <= '2002-07-05'
      AND name_id = 2
    ORDER BY 
      date DESC
    LIMIT 9 ) temp

The inner query returns all filtered rows in desc order, and then you avg, sum up those rows returned.

The reason why the query given by you doesn't work is due to the fact that the sum is calculated first and the LIMIT clause is applied after the sum has already been calculated, giving you the sum of all the rows present