I have created new measure that counts distinct policies (this measure is called FK Policy Distinct Count).
Then I created new calculated member called CountPolicyEndorsesNull which counts all policies from FK Policy Distinct Count using a filter:
(([Policy].[Endorses].&[0],[FK Policy Distinct Count]).
Than I did new calculated member called CountPolicy:
SUM(EXCEPT([Policy].[Policy Status].[Policy Status],[Policy].[Policy Status].&[Void]), [Measures].[CountPolicyEndorsesNull])
Next, I created a new member CountNewBound
SUM(
{
[Submission].[Tran Type].&[New], [Submission].[Tran Type].&[Developed]
},
[Measures].[CountPolicy]
)
And finally, YTDCountNewBound
SUM(YTD([Invoice Date].[Date Hierarchy].CurrentMember), [Measures].[CountNewBound])
Obviously, SUM function doesn't work in this case. Any idea how to make proper YTD count for calculated member?
Distinct count is a special measure which should be managed with a little more care. The rational behind this is that the when evaluating the measure a set of previous values is kept in memory. In order to improve performance, this structure is not passed and it's quickly converted to a scalar value.
Going back to your problem :
Distinct count can be evaluated over a tuple without problem, but you'll get in problems once you try to evaluate over a set of tuples. A possible, but costly and not always possible, is to create a hierarchy of values so you can convert your set in a member of a dimension.
In your case instead of using YTD([Invoice Date].[Date Hierarchy].CurrentMember) function using another hierarchy -> [Invoice Date].[YTD Date Hierarchy].
All this depends on the specific OLAP implementation you're using, but I guess holds true for mainly all OLAP vendors.
Related
I have a measure [Measures].[myMeasure] that I would like to create several derivatives of based on the related attribute values.
e.g. if the related [Location].[City].[City].Value = "Austin" then I want the new calculated measure to return the value of [Measures].[myMeasure], otherwise, I want the new calculated measure to return 0.
Also, I need the measure to aggregate correctly meaning sum all of the leaf level values to create a total.
The below works at the leaf level or as long as the current member is set to Austin...
Create Member CurrentCube.[Measures].[NewMeasure] as
iif(
[Location].[City].currentmember = [Location].[City].&[Austin],
[Measures].[myMeasure],
0
);
This has 2 problems.
1 - I don't always have [Location].[City] in context.
2. When multiple cities are selected this return 0.
I'm looking for a solution that would work regardless of whether the related dimension is in context and will roll up by summing the atomic values based on a formula similar to above.
To add more context consider a transaction table with an amount field. I want to convert that amount into measures such as payments, deposits, return, etc... based on the related account.
I don't know the answer but just a couple of general helpers:
1 You should use IS rather than = when comparing to a member
2 You should use null rather than 0 - 0/NULL are effecitvely the same but using 0 will slow things up a lot as the calculation will be fired many more times. (this might help with the second section of your question)
Create Member CurrentCube.[Measures].[NewMeasure] as
iif(
[Location].[City].currentmember IS [Location].[City].&[Austin],
[Measures].[myMeasure],
NULL
);
I understand how to use the MDX Aggregate() and Sum() functions, and the differences between them.
(One interesting one is that the Sum of a measure defined at a higher level in a hierarchy over that level's Children multiplies the measure by the number of children - whereas Aggregate "correctly" returns just the value defined at the higher level).
The documented syntax on MSDN is:
Aggregate(Set_Expression [ ,Numeric_Expression ])
I've always used it with both arguments. But what does Aggregate do when only the set_expression argument is provided? The documentation (again from MSDN) is pretty obscure:
If a numeric expression is not provided, this function aggregates each measure within the current query context by using the default aggregation operator that is specified for each measure.
I tried it in an MDX query like this:
WITH MEMBER WeekSummedTotal AS
Aggregate([Days].[WeeksAndDays].CurrentMember.Children)
SELECT
{Measures.ThingoCount,Measures.WeekTotal,Measures.WeekSummedTotal} ON 0,
[Days].[WeeksAndDays].[WeekName] ON 1
FROM DateGRoupingTest
What would this do? Would Aggregate aggregate the cube's default measure over the set? Or the set Measures.Members? Or the set of other measures specified on the 0 axis?
None of these! The query runs and returns results, but the calcd measure WeekSumTotal shows #Error, with a completely nonsensical error:
Aggregate functions cannot be used on calculated members in the measures dimension
Now this is true, but completely irrelevant. None of the other measures in the query is calculated, and in fact the cube doesn't have any calculated members. So what is Aggregate() actually trying to do here? Is this error message (again, in MDX!) completely misleading?
ADDITION: #whytheq in the answer below suggested creating the calculated measure using Aggregate, but creating it on a spare dimension hierarchy rather than in the Measures dimension. This works, but only if the cross-join with the [All] member of the selected "any old..." dimension is included.
Creating the measure there also makes it impossible to put the two (base) measures and the calculated measure on the same axis. If I try to do this:
{Measures.ThingoCount,Measures.WeekTotal,[Ages].[Age Key].WeekSummedTotal} ON 0,
I get the deeply-unhelpful error message:
Members, tuples or sets must use the same hierarchies in the function.
which, I think, translates to "I can't make a set using the , (UNION) function between members of Measures and members of [Ages].[Age Key] because they're members of different dimensions".
My conclusion, thanks to your informative answers, is that Aggregate() with a single argument is a tricky beast; I wonder why it was designed with the second argument optional?
I've also noted that trying to create my calculated member on my Ages dimension (only one hierarchy, only one attribute) gives me the misleading error message:
The 'Ages' dimension contains more than one hierarchy, therefore
the hierarchy must be explicitly specified.
unless I explicitly specify the hierarchy. MDX has so much potential, but the learning curve would be that much gentler if MS had put more effort into making it feed back errors properly.
What would this do? Would Aggregate aggregate the cube's default
measure over the set? Or the set Measures.Members? Or the set of other
measures specified on the 0 axis?
Aggregate function aggregates the set over the current measure for Measures dimension. And a measure is "current" if it is in scope. If a measure is not in scope, the default member from measures dimension is considered for aggregation.
A measure can be added to scope in many ways like
Having the measure on axes
with member [Customer].[Customer].abc as
aggregate([Customer].[Customer].members)
select [Customer].[Customer].abc on 0,
{[Measures].[Internet Sales Amount],[Measures].[Reseller Sales Amount]} on 1
from [Adventure Works]
In the above example the member abc was calcualted twice, once for each measure.
Using Subcube
with member [Customer].[Customer].abc as
aggregate([Customer].[Customer].members)
select [Customer].[Customer].abc on 0
from (select {[Measures].[Internet Sales Amount] } on 0 from [Adventure Works])
Having the measure in definition
with member [Customer].[Customer].abc as
aggregate([Customer].[Customer].members, [Measures].[Internet Sales Amount])
select [Customer].[Customer].abc on 0
from [Adventure Works]
In Where clause
with member [Customer].[Customer].abc as
aggregate([Customer].[Customer].members)
select [Customer].[Customer].abc on 0
from [Adventure Works]
where [Measures].[Internet Sales Amount]
As suggested by whytheq, have the member on some other dimension-hierarchy combo. Otherwise, the aggregate function would probably lead to the calculated member self-referencing itself.
Taking this section of the MSDN definition:
...this function aggregates each measure within the current query
context ...
each measure in the context of your script is the following:
{Measures.ThingoCount,Measures.WeekTotal,Measures.WeekSummedTotal}
Now Measures.WeekSummedTotal is a calculated members in the measures dimension - hence the error.
I'd imagine something like the following would function ok, where you use Aggregate to create a member in a dimension other than Measures?:
WITH
MEMBER [SomeSpareDim].[SomeSpareHier].WeekSummedTotal AS
Aggregate
(
[Days].[WeeksAndDays].CurrentMember.Children * [SomeDim].[SomeHier].[All]
)
SELECT
[SomeSpareDim].[SomeSpareHier].WeekSummedTotal ON 0
,[Days].[WeeksAndDays].[WeekName] ON 1
FROM DateGRoupingTest;
The above can be changed to show Aggregate being very useful:
WITH
MEMBER [Days].[WeeksAndDays].[Last3Weeks] AS
Aggregate
(
{
[Days].[WeeksAndDays].[Weekx]
,[Days].[WeeksAndDays].[Weeky]
,[Days].[WeeksAndDays].[Weekz]
}
)
SELECT
{Measures.ThingoCount,Measures.WeekTotal} ON 0
,{
//<< the following custom aggregated member will work for any measure, that is ON 0, via Aggregate
//it can be mixed up with the normal members of the same hierarchy like the following
[Days].[WeeksAndDays].[Last3Weeks]
,[Days].[WeeksAndDays].[WeekName].members
} ON 1
FROM DateGRoupingTest;
I've been looking around for the answer but I didn't find anything. Sorry if the answer has been given elsewhere.
Here is my problem :
I have a calculated member which is the number of items (of the current member) divided by the total number of items (sumitem).
with
member
sumitem
as
SUM ([FailureReason].[FailureReason].[All],[Measures].[Items])
member
Impact
as
[Measures].[Items]/[Measures].[SumItem]
But for a specific member of my dimension FailureReason, the result of Impact has to be 0. So I tried to add this :
member
ImpactFinal
as
iif ([FailureReason].CurrentMember = [FailureReason].[FailureReason].&[127],
0,
Impact
)
and I select my data like this :
select
{[Measures].[Items],
ImpactFinal
} on columns,
[FailureReason].members on rows
from
NoOTAR
But instead of getting 0 only for this specific member, every members of this dimension have their ImpactFinal equals to 0. What is strange is if I replace 0 by any other value, the result is good.
Just use
[FailureReason].CurrentMember IS [FailureReason].[FailureReason].&[127]
instead of
[FailureReason].CurrentMember = [FailureReason].[FailureReason].&[127]
and it will work.
Update: Several tips:
There is also not necessary to use SUM function, since you can define only tuple, this will be enough for server: ([FailureReason].[FailureReason].[All],[Measures].[Count])
It's quite reasonable to check sumitem measure for dividing by zero in ImpactFinal calculation. Because once some filters are applied, this may cause zeroing this measure and errors in reports.
If you have an opportunity not only to query, but update cube, SCOPE ([FailureReason].[FailureReason].&[127],[Measures].[Impact]) with THIS = 0 is better than additional member because of performance.
Best of luck!
UPDATE to fix totals:
If total should be w/o FailureReason 127, you can substitute your measures with:
member Impact
as
iif ([FailureReason].[FailureReason].CurrentMember is [FailureReason].[FailureReason].&[127],
0,
[Measures].[Items]
)
member ImpactFinal
as
iif ([FailureReason].[FailureReason].CurrentMember is [FailureReason].[FailureReason].[All]
,[Measures].[Items]-([FailureReason].[FailureReason].&[127],[Measures].[Items])
,[Measures].[Impact])/[Measures].[SumItem]
But I have another solution, which is more readable:
member v2_ImpactUncountableFailure
as
iif ([FailureReason].[FailureReason].CurrentMember.Level.Ordinal=0
or
[FailureReason].[FailureReason].CurrentMember is [FailureReason].[FailureReason].&[127]
,([FailureReason].[FailureReason].&[127],[Measures].[Items])
,null)
member v2_ImpactFinal
as
([Measures].[Items]-[Measures].[v2_ImpactUncountableFailure])
/
([FailureReason].[FailureReason].[All],[Measures].[Items])
Use only this two measures instead of set of measures sumitem,Impact,ImpactFinal. First one will show result on failure-127 and total. Second subtracts it from clean unfiltered measure, so in the end we have clean members, zeroed failure-127 and corrected total.
Please let me know if it isn't work, I've tested on my DB and everything is OK.
A simple CASE statement would solve your problem: Try this
With
Member ImpactFinal As
CASE
WHEN [FailureReason].[FailureReason].CurrentMember IS [FailureReason].[FailureReason].&[127] THEN 0
ELSE
[Measures].[Items]
/
([FailureReason].[FailureReason].[All], [Measures].[Items])
END
SELECT
{ [Measures].[Items], ImpactFinal } On Columns
[FailureReason].[FailureReason].Members On Rows
From NoOTAR
Try
with
member sumitem
as
SUM ([FailureReason].[FailureReason].[All],[Measures].[Items])
member LeaveOut
as
[FailureReason].[FailureReason].CurrentMember.Properties("Key")
member Impact
as
IIf([Measures].[LeaveOut]= "127", 0, [Measures].[Items]/[Measures].[SumItem])
I have a question related to creating a (more efficient) custom Distinct Count Measure using MDX.
Background
My cube has several long many to many relationship chains between Facts and Dimensions and it is important for me to be able to track which members in certain Dimensions do and do not relate to other Dimensions. As such, I have created a "Not Related" record in each of my dimension tables and set those records' ID values to -1. Then in my intermediate mapping fact tables I use the -1 ID to connect to these "Not Related" records.
The issue arises when I try to run a normal out-of-the-box distinct count on any field where the -1 members are present. In the case that a -1 member exists, the distinct count measure will return a result of 1 more than the true answer.
To solve this issue I have written the following MDX:
CREATE MEMBER CURRENTCUBE.[Measures].[Provider DCount]
AS
//Oddly enough MDX seems to require that the PID (Provider ID) field be different from both the linking field and the user sliceable field.
SUM( [Providers].[PID Used For MDX].Children ,
//Don't count the 'No Related Record' item.
IIF( NOT([Providers].[PID Used For MDX].CURRENTMEMBER IS [Providers].[PID Used For MDX].&[-1])
//For some reason this seems to be necessary to calculate the Unknown Member correctly.
//The "Regular Provider DCount Measure" below is the out-of-the-box, non-MDX measure built off the same field, and is not shown in the final output.
AND [Measures].[Regular Provider DCount Measure] > 0 , 1 , NULL )
),
VISIBLE = 1 , DISPLAY_FOLDER = 'Distinct Count Measures' ;
The Issue
This MDX works and always shows the correct answer (yeah!), but it is EXTREMELY slow when users start pulling Pivot Tables with more than a few hundred cells that use this measure. For less than 100 cells, the results are nearly instantaneously. For a few thousand cells (which is not uncommon at all), the results could take up to an hour to resolve (uggghhh!).
Can anyone help show me how to write a more efficient MDX formula to accomplish this task? Your help would be GREATLY appreciated!!
Jon Oakdale
jonoakdale#hotmail.com
Jon
You can use predefined scope to nullify all unnecessary (-1) members and than create your measure.
SCOPE ([Providers].[PID Used For MDX].&[-1]
,[Measures].[Regular Provider DCount Measure]);
THIS = NULL;
END SCOPE;
CREATE MEMBER CURRENTCUBE.[Measures].[Provider DCount]
AS
SUM([Providers].[PID Used For MDX].Children
,[Measures].[Regular Provider DCount Measure]),
VISIBLE = 1;
By the way, I used in my tests [Providers].[PID Used For MDX].[All].Children construction since don't know, what is dimension / hierarchy / ALL-level in your case. It seems like [PID Used For MDX] is ALL-level and [Providers] is name of dimension and hierarchy, and HierarchyUniqueName is set to Hide.
Being an SSAS newbie, I was wondering if it's possible to create a calculated member that references an individual row's value as well as the aggregated value in order to create a percentage?
For example, if I have a fact table with ValueA, I'd like to create a calculate member that essentially performed:
[Measures].[ValueA] (for each row I've sliced the data by) / [Measures].[ValueA] (the total)
Also I'd like to keep the total as the sum of whatever's been filtered in the cube browser. I feel certain this must be possible but I'm clearly missing something.
You can use the Axis function. Her is an example:
WITH MEMBER [Measures].[Percentage] AS
[Measures].[ValueA] / (Axis(1).CurrenMember.Parent, [Measures].[ValueA])
SELECT {[Measures].[ValueA], [Measures].[Percentage]} ON 0,
'what you want' ON 1
FROM your cube
(You may need to add check in the calculated member expression)