--- In firebird-support@yahoogroups.com, "Todd Brasseur"
<todd.compass-cama@h...> wrote:

>
> We are looking for a way to calculate some statistics.
>
> The main statistic that we need is a 'median' (the middle occurance of
> a list of values).
>
> Ideally, we would have a function that we could use in stored
> procedures that would work like avg, min, max, etc.:
>
> Select Location, median(Ratio) From Sales Group By Location
>
> Is the median something that would have to be added to Interbase (or
> Firebird) itself (the same as avg, min, max, etc.) or is it something
> that we could write ourselves? Does the SQL Standard include a median?
>
> The only way I can think of doing it is to process data twice directly
> in the stored procedure. Once to get the 'count' and then again with
> an order by and counter to get the middle (or middle two) values.
> This is a real pain because we need to calculate the median quite
> often. It also makes things slow. It is so easy in Clipper as we
> simply pass a function an array.
>
> We also need to be able to calculate a 'square root' and 'logarithms'.
>
> Any ideas would be greatly appreciated.
>
> Todd
>

Todd,
I've only ever done this in the client.
Someone showed some interesting SQL - beyond me - that returned
statistical values.
Logs - use a UDF
mick