Standard deviation

[#1]

Hello,

I have a only one table with one row:

LOAD * INLINE [

    ITEMID, INVENTLOCATION, DATE, sales

    026381, Ł1, 2013-Mar, 1

];

I want to create table with calculation of standard deviation:

dimension: ITEMID,INVENTLOCATION

expression: =stdev(aggr(sum(sales),INVENTLOCATION, DATE))

Why field of this expression is empty?

[Clever_Anjos · Accepted solution]

Standard Deviation calculation needs at least two values

If you have only one value, you´ll have 0/0 that is undefined

[#3]

the same result with this script:

LOAD * INLINE [

    ITEMID, INVENTLOCATION, DATE, sales

    026381, Ł1, 2013-Mar, 1

    026381, Ł1, 2013-Mar, 1

];

[Clever_Anjos]

Again, you´re having only one value, since your INVENTLOCATION, DATE are the same, so your AGGR() will return only one value.

LOAD * INLINE [

    ITEMID, INVENTLOCATION, DATE, sales

    026381, Ł1, 2013-Mar, 1

    026381, Ł1, 2013-Abr, 1

];

will return "0", because your AGGR() will return 2 similars values

[#5]

Ok, I have problem with this. Why when I don't selected ITEMID expression =stdev(aggr(sum(sales),INVENTLOCATION, DATE)) is not calculated for all ITEMID. When I select only one ITEMID this expression is calculated?

[Clever_Anjos]

Could you post a sample of your app?

[#7]

In attachment

[Clever_Anjos]

If you use an AGGR inside an object that has dimensions usually those dimensions must be into your aggr expression.

Please check if this formula returns what you need

=stdev(aggr(sum(ilosczfak),ITEMID,INVENTLOCATIONIDLOG2, INVOICEMONTH))

[Clever_Anjos]

Please check #4 into Pitfalls of the Aggr function