SQL sum and divide by number of results

Question

Can't get it to work... this is what I got so far:

SELECT CardCode, (sum(DocRate) DocRate/DocRate.Length)
FROM OPCH
WHERE DocRate > 1
  AND DocStatus = 'O'
  AND DocDate >= '20140101'
GROUP BY CardCode

Trying to get the sum of DocRate (which is diffrent each row) and divide it with number of rows (to get an average).

This isn't working.

Answer 1

Well easy enough, found the solution.
Using AVG().

My code:

SELECT CardCode,
       avg(DocRate) DocRate
FROM OPCH
WHERE DocRate > 1
  AND DocStatus = 'O'
  AND DocDate >= '20140101'
GROUP BY CardCode

Answer 2

Try using sub query.

SELECT CardCode, (DocRate/length)
FROM
  (SELECT CardCode,sum(DocRate) DocRate, sum (DocRate.Length) length
FROM OPCH
WHERE DocRate > 1
  AND DocStatus = 'O'
  AND DocDate >= '20140101'
GROUP BY CardCode) doc
GROUP BY CardCode