On Thursday, May 24, 2018, Ron <
ronljohnsonjr@gmail.com> wrote:
On 05/24/2018 10:15 AM, Martin Mueller wrote:
You construct a z-score for a set of values by subtracting the average from the value and dividing the result by the standard deviation. I know how to do this in a two-step procedure. First, I compute the average and standard deviation. In a second run I use the formula and apply it to each value.
Is there a way of doing this in a single-step procedure or can you chain the two parts together in one query? This goes beyond my SQL competence.
What about this?
SELECT value, (value - AVG(value))/stddev(value) as zvalue
FROM sometable
WHERE some conditions
GROUP by value
That is syntactically correct but doesn't provide the correct answer.
David J.