I require some more advanced MDX knowledge than mine.
I need to get the RepoRate_MAX for repo products, at book and instrument level, but also looking at the Java code I'm replacing that code always uses the max MurexId.
How can I perform the below (I've placed MAX in here on the dimension but this is wrong) and I need the combo of the dimensions and also the MAX MurexId:
[Measures].[RepoRate_VAL] = (([Deal].[ProductType].&[REPO],[Deal].[Book],[Deal].[Instrument],MAX([Deal].[MurexId])),[Measures].[RepoRate_MAX])
I'm sure it's a simple one but my mind is part way between the Java OO and MDX worlds currently haha :D
Thanks
Leigh
So after some experimenting I found out about the TAIL and Item MDX functions.
I think at one point I did get it working, but didn't make a note of what did work. I was playing around with this and variants of it..but most versions ended up in unusable query times:
[Measures].[RepoRate_VAL] = (([Deal].[ProductType].&[REPO],[Deal].[Book],[Deal].[Instrument],TAIL(EXISTING([Deal].[MurexId].[MurexId])).Item(0)),[Measures].[RepoRate_MAX])
So I then decided to push the RepoRate calculation back to the SQL data preparation script. Cleaner/smoother data is always better and then to have simple calculated members.
I used SQL to determine the RepoRate from tradelevel with MAX(MurexId) and GROUP BY on Book, Instrument to then update my main fact table to ensure that the correct RepoRate was set at Book, Instrument level.
Thus the calculated member is then:
[Measures].[RepoRate_VAL] = (([Deal].[Book],[Deal].[Instrument]),[Measures].[RepoRate_MAX])
Fast data prep and a fast calculated member on the Excel/Pivot/UI layer.
Scenario
Designing a Star Diagram for an OLAP environment for the process Incident Management. Management requests to be able to both filter on SLA status (breached, achieved or in progress) and being able to calculate the percentage of sla achieved vs breached. Reporting will be done through in Excel/SSRS through SSAS (tabular).
Question
I’m reasonable inexperienced in designing for an OLAP environment. I know my idea will work but I’m concerned this is not the best approach.
My idea:
SLA needs to be both a measure and a dimension.
DimSLA
…
(Nullable bool) Sla Achieved -> Yes=True, No=False, and InProgress=NULL
…
FactIncident
…
(Nullable Integer) Sla Achieved Yes=1,No=0 and In Progress=NULL
…
Then in SSAS, publish a calculated percentage field which averages FactIncident-SlaAchieved.
Is this the right/advisable way to do it?
As you describe it, "SLA achieved" should be an attribute, as you want to classify by it, not sum it. The only thing you want to sum or aggregate would be other measures (maybe an incident count) under the condition that the "SLA achieved" attribute has certain values like "achieved" or "not achieved". This is the main rule in dimensional design: Things you use for classifying or break down are attributes, and things that you calculate are measures. There are a few cases where you need a column for both, but not many.
Do not just use a boolean value. Use a string value easily understand by users like the texts "SLA achieved", "SLA not achieved", "in progress". This makes it much more easy for non technical users to use the cube. In case you use this in a dimension table , there would be just three records with the strings, and the fact table would reference them with maybe a byte foreign key, hence more meaningful texts do not use up millions of bytes.
Is there such a thing as a constant in SSAS?
Example (this is really happening where I'm at) everyone agrees that gigs to mb be converted by 1000 (not 1024) and tb to mb by 1000000.
Where would you store a number like that used across the board?
If it's inside the cube, could you create a calculated member that stores it? Define it in the cube's calculation script, it's fine with constants in there.
In cube calculation script:
CREATE MEMBER CURRENTCUBE.Measures.MBtoGigs AS 1000
Query against the cube:
SELECT Measures.MBtoGigs ON COLUMNS FROM [Cube]
One possible pitfall I would point out, is that using constants like this can alter the way you'd expect the NON EMPTY behaviour to work in your queries - As a constant is never 'empty'.
Having said that, you can define you own non-empty-behaviour for calculated measures, so remember to try that with any calculated measures that involve constants if you experience any issues.
where\how do you need to use it?
you can always create a fact table with a column with that value (1000), whitch will become a measure group, and set the aggregation type on the measure with to "lastNonempty".
Since this value is on its own MG it can be easly used on the expression property of another measure on a different MG
I have a SSAS cube in which there is a measure that needs to be allocated via a percentage located in another measure. I have all this set up as a Measure Expression in my "Equity Amount" measure and it works great.
My problem is that this "Equity Amount" measure is actually a snapshot so I would need it to aggregate using the LastChild function. It turns out that you cannot have a measure expression in a semi additive measure so i'm trying to fake the LastChild function in MDX.
I've seen a lot of examples everywhere on the web and all but none of them talk about having multiple hierarchies in the date dimension. I have both "calendar Year" and "Fiscal Year" hierarchies.
My MDX works for one hierarchy but as soon as I scope for the second hierarchy, the first one gets overwritten. I'm guessing I need to treat both hierarchies in a single statement but am having a real tough time getting it to work.
Here is my MDX for one hierarchy. Can anyone help modify it for multiple hierarchies or is there any other way to solve my problem ?
Scope([Measures].[Equity Value]);
This = iif(isleaf([Calendar].[By Calendar Year].CurrentMember),
[Measures].[Equity Value],
([Calendar].[By Calendar Year].CurrentMember.LastChild,[Measures].[Equity Value]));
End Scope;
David,
1) You're using scope as a calculated member. You can get rid of your iif by declaring the scope working only in a sub-cube :
scope ([Measures].[Equity Value],[Calendar].[By Calendar Year].levels(0).... )
This = (the expression)
2) Not sure to understand your problem but a tuple with two members of two hierarchies of the same dimension can be null by construction: As an example your first day of the calendar (1/1/2010) and the first day of your fiscal calendar (e.g. 1/6/2020) are not the same day so actually null. Two hierarchies of a same dimension are only ways of representing the same coordindates (here days), you're doing an intersection by declaring a tuple.
Not sure I'm helping you...
Thanks for trying! I understand what you mean (I think). MDX is one tough language!
I ended up doing the allocation via the view that is the source for my measure and keeping the LastChild aggregation function for the measure. In the end, it is much easier and also is better for query performance.
Thanks anyway :)
BACKGROUND:
I've been trying to streamline the work involved in running a report in my program. Lately, I've had to supply a listing of job numbers an instrument has been used on with the listing of items for cost/benefit analysis. Mostly to see how often an instrument is used since it was last serviced/calibrated and the last time anyone did use it. I was looking to integrate this into the query that helps generate the report - but I keep hitting a brick wall of sorts with the number of uses - since I want that aggregate to be based on the date the instrument was last calibrated (a field based in the same query). I can get it to give me the number of uses in the system total - but it will not accept the limitation that I want it to be only counting the times used since the last time it was calibrated
PROBLEM:
Attempts to put an aggregate function in my report for the number of uses since the item's calibration are met either with undesired results, or the dreaded 'aggregate missing' error (don't remember the exact warning).
-- Edited to add 8/12/2011 # 16:09 --
An additional problem with the use of the Max aggregate has been found for instruments that have never been used being excluded by this query.
DETAILS:
Here is the query that does work so far:
SELECT
dbo_tblPOGaugeDetail.intGagePOID,
dbo_tblPOGaugeDetail.strGageDetailID,
dbo_Gage_Master.Description,
dbo_Gage_Master.Manufacturer,
dbo_Gage_Master.Model_No,
dbo_Gage_Master.Gage_SN,
dbo_Gage_Master.Unit_of_Meas,
dbo_Gage_Master.User_Defined,
dbo_Gage_Master.Calibration_Frequency,
dbo_Gage_Master.Calibration_Frequency_UOM,
dbo_tblPOGaugeDetail.bolGageLeavePriceBlank,
dbo_tblPOGaugeDetail.intGageCost,
dbo_Gage_Master.Last_Calibration_Date,
dbo_Gage_Master.Next_Due_Date,
dbo_tblPOGaugeDetail.bolGageEvaluate,
dbo_tblPOGaugeDetail.bolGageExpedite,
dbo_tblPOGaugeDetail.bolGageAccredited,
dbo_tblPOGaugeDetail.bolGageCalibrate,
dbo_tblPOGaugeDetail.bolGageRepair,
dbo_tblPOGaugeDetail.bolGageReturned,
dbo_tblPOGaugeDetail.bolGageBER,
dbo_tblPOGaugeDetail.intTurnaroundDaysOut,
qryRCEquipmentLastUse.MaxOfdatDateEntered
FROM (dbo_tblPOGaugeDetail
INNER JOIN dbo_Gage_Master ON dbo_tblPOGaugeDetail.strGageDetailID = dbo_Gage_Master.Gage_ID)
INNER JOIN qryRCEquipmentLastUse ON dbo_Gage_Master.Gage_ID = qryRCEquipmentLastUse.Gage_ID
ORDER BY dbo_tblPOGaugeDetail.strGageDetailID;
But I can't seem to aggregate a count of Uses (making a Count(strCustomerJobNum)) from the tblGageActivity with the following fields:
strGageID
strCustomerJobNum
datDateEntered
datTimeEntered
I tried to add a field to the formerly listed query to do a Count(strCustomerJobNum) where datDateEntered matched the Last_Calibration_Date from the calling query - but I got the 'missing aggregate' error. If I leave this condition out - it will run - but will list every instrument ever sent out only if it's had a usage count of at least one (not what I want at all, sadly).
I also want to make sure that if I should get a zero uses count - I will get a zero back instead of my expected records minus the null results.
I hope someone out there can tell me where I am going wrong with this - I want to save the time I am currently spending running an activity report in another program whenever I want to generate this report. Thanks in advance, and let me know if you need me to post more information.
-- Edited to add 08/15/2011 # 14:41 --
I managed to solve the Max() aggregate problem by creating a 'pure' first-step query to get a listing of all instrument with most modern date as qryRCEquipmentUsed.
qryRCEquipmentLastUse:
SELECT dbo.tblGageActivity.strGageID, Max(dbo.tblGageActivity.datDateEntered) AS datLastDateUsed
FROM dbo.tblGageActivity
GROUP BY dbo.tblGageActivity.strGageID;
Then I created a 'pure' listing of all instruments that have no usage at all as a query named qryRCEquipmentNeverUsed.
qryRCEquipmentNeverUsed:
SELECT dbo_Gage_Master.Gage_ID, NULL AS datLastDateUsed
FROM dbo_Gage_Master LEFT JOIN dbo_tblGageActivity ON dbo_Gage_Master.Gage_ID = dbo_tblGageActivity.strGageID
WHERE (((dbo_tblGageActivity.strGageID) Is Null));
NOTE: The NULL was inserted so that the third combining UNION query will not fail due to a mismatch in the number of fields being retrieved from the tables.
At last, I created a UNION query named qryCombinedUseEquipment to combine the two into a list:
qryCombinedUseEquipment:
SELECT *
FROM qryRCEquipmentLastUse
UNION SELECT *
FROM qryRCEquipmentNeverUsed;
Using this last union query to feed the Last Used date to the parent query works in datasheet view, but when the parent query is called in the report - I get a blank report; so a nudge in the right direction would still be wonderfully appreciated.
APPENDIX
Same script as above, but with shorter table aliases (in case someone finds that clearer):
SELECT
gd.intGagePOID,
gd.strGageDetailID,
gm.Description,
gm.Manufacturer,
gm.Model_No,
gm.Gage_SN,
gm.Unit_of_Meas,
gm.User_Defined,
gm.Calibration_Frequency,
gm.Calibration_Frequency_UOM,
gd.bolGageLeavePriceBlank,
gd.intGageCost,
gm.Last_Calibration_Date,
gm.Next_Due_Date,
gd.bolGageEvaluate,
gd.bolGageExpedite,
gd.bolGageAccredited,
gd.bolGageCalibrate,
gd.bolGageRepair,
gd.bolGageReturned,
gd.bolGageBER,
gd.intTurnaroundDaysOut,
lu.MaxOfdatDateEntered
FROM (dbo_tblPOGaugeDetail gd
INNER JOIN dbo_Gage_Master gm ON gd.strGageDetailID = gm.Gage_ID)
INNER JOIN qryRCEquipmentLastUse lu ON gm.Gage_ID = lu.Gage_ID
ORDER BY gd.strGageDetailID;
Piece by piece...
First -- I suspect you're trying to answer too many questions at once (as evidenced by 23 fields in your SELECT), which will make aggregation near-impossible. Start by narrowing down the scope of the query -- What question is this query attempting to answer? (You can always make more queries to answer other questions... :-)
1) How many uses since last calibration?
2) How many uses since last ...use? (not sure what you mean by that -- maybe last sign-out, or last rental, etc.?)
Tip -- learn to use table aliases. Large queries are difficult to read; worse because of repeated table names.
1) Ex.: dbo_tbl_POGaugeDetail.intGagePOID becomes d.intGagePOID
Here's a sample that might get you started:
SELECT
d.strCustomerJobNum,
Max(d.last_calibration_date) -- not sure what you named that field
Count(d.strCustomerJobNum)
FROM
dbo_tblPOGaugeDetail d
GROUP BY
d.strCustomerJobNum
Does this work:
SELECT dbo_tblPOGaugeDetail.intGagePOID, dbo_tblPOGaugeDetail.strGageDetailID,
OuterGageMaster.Description, OuterGageMaster.Manufacturer, OuterGageMaster.Model_No,
OuterGageMaster.Gage_SN, OuterGageMaster.Unit_of_Meas, OuterGageMaster.User_Defined,
OuterGageMaster.Calibration_Frequency, OuterGageMaster.Calibration_Frequency_UOM,
dbo_tblPOGaugeDetail.bolGageLeavePriceBlank, dbo_tblPOGaugeDetail.intGageCost,
OuterGageMaster.Last_Calibration_Date, OuterGageMasterNext_Due_Date,
dbo_tblPOGaugeDetail.bolGageEvaluate, dbo_tblPOGaugeDetail.bolGageExpedite,
dbo_tblPOGaugeDetail.bolGageAccredited, dbo_tblPOGaugeDetail.bolGageCalibrate,
dbo_tblPOGaugeDetail.bolGageRepair, dbo_tblPOGaugeDetail.bolGageReturned,
dbo_tblPOGaugeDetail.bolGageBER, dbo_tblPOGaugeDetail.intTurnaroundDaysOut,
qryRCEquipmentLastUse.MaxOfdatDateEntered,
(Select Count(strCustomerJobNum)
FROM tblGageActivity WHERE
OuterGageMaster.Last_Calibration_Date=tblGageActivity.datDateEntered) As JobCount
FROM
(dbo_tblPOGaugeDetail INNER JOIN dbo_Gage_Master OuterGageMaster ON
dbo_tblPOGaugeDetail.strGageDetailID = OuterGageMaster.Gage_ID) INNER JOIN
qryRCEquipmentLastUse ON OuterGageMaster.Gage_ID = qryRCEquipmentLastUse.Gage_ID
ORDER BY
dbo_tblPOGaugeDetail.strGageDetailID;
or is that what you tried?
Summary Problem:
Attempts to put an aggregate function in my report for the number of uses since the item's calibration are met either with undesired results, or the dreaded 'aggregate missing' error.
Solution:
I decided to leave the query driving the report alone - instead choosing to employ the use of DLookup and DCount as appropriate to retrieve the last used date from a query that provides the last used date of all the instruments, and the number of uses an instrument has had since it's last calibration, using the aforementioned domain aggregates respectively.
Using the query described in the problem description, I am able to retrieve the last used date for all instruments. I used a =DLookup statement as the source for a text box on the report's subreport dealing with various items as such:
=IIf((DLookUp("[qryRCCombinedUseEquipment]![datLastDateUsed]","[qryRCCombinedUseEquipment]","[qryRCCombinedUseEquipment]![strGageID]=[strGageDetailID]")) Is Null Or ([bolGageReturned]=True),"",DLookUp("[qryRCCombinedUseEquipment]![datLastDateUsed]","[qryRCCombinedUseEquipment]","[qryRCCombinedUseEquipment]![strGageID]=[strGageDetailID]"))
This allows items that have never been used to return a NULL result, which will display as a blank text box.
The number of uses, however, would not feed off a query using =DCount (I tried, it would take over ten minutes to retrieve results, if it ever did). However, using the underlying activity table, I used the following statement:
=IIf([bolGageReturned],"","Used " & DCount("[dbo_tblGageActivity]![strGageID]","[dbo_tblGageActivity]","[dbo_tblGageActivity]![strGageID] = [strGageDetailID] And [dbo_tblGageActivity]![datDateEntered] Between [txtLastCalibrationDate] And date()") & " times since last calibration")
It would retrieve a number of times used since the instrument was last calibrated, but no uses that are before that or after today (some jobs are post dated, strangely). Of course, this is SLOW (about thirty seconds for a large document with thirty or forty instruments).
Does anyone else have a better solution for this, or will I have to take the performance hit? If no one has any better ideas, I will accept this as the answer after five days (8/21/2011) .