I have a Power BI data model with a DAX calculated table used as a dimension that is calculated with VALUES from a fact table with multiple occurrences of each value, so it is a 1:M relationship.
In my report I want to use the calculated table values as a slicer with the options presented in a specific order other than alphabetical. Therefore in the calculated table, I created a calculated column that assigns a number to each row based on a SWITCH function. However, when I then try to "Sort by Column" in Power BI, it throws an error indicating that it is a circular reference. How else can I define the sort order?
Here is an example data/calculated tables:
'Source' fact table:
Dimension_Values
a_order_third
a_order_third
b_order_first
b_order_first
c_order_second
c_order_second
Calculated_Dim_Table = VALUES('Source'[Dimension_Values])
Dimension_Values
a_order_third
b_order_first
c_order_second
Calculated_Order_Column = SWITCH('Calculated_Dim_Table'[Dimension_Values],"b_order_first",1,"c_order_second",2,"a_order_third",3)
*Sort 'Calculated_Dim_Table'[Dimension_Values] by 'Calculated_Dim_Table[Calculated_Order_Column] so that desired output is
Dimension_Values
Calculated_Order_Column
b_order_first
1
c_order_second
2
a_order_third
3
Issue: Power BI is saying this is creating a circular dependency - is there another way to define the sort order of a column without referencing it to avoid the circular dependency?
I think it throws an circular reference error, caused DAX internally decides the the order of execution. In this case, DAX wants to sort the dimension values upon loading, but it can't cause it depends on a calculated column thst in turn depends on dimension values. So it is a circular reference indeed. I would advise you to this in PQ and then load both the tables and then you can do the sorting in t2 with no trouble.
Related
I have this DAX formula that gives me a count of id that appear on the fact table in a month, averaged over the year. I can put this measure is a table ad it's unpacked by row with no issues (by adding variables from dimensions)
Measure:= AVERAGEX(
SUMMARIZE(
CALCULATETABLE(fact_table;FILTER('Time_Dimension';'Time_Dimension'[Last_month] <> "LAST"));
Time_Dimension[Month Name];
"Count";DISTINCTCOUNT(fact_table[ID])
);
[Count]
)
But it's terrible slow (I have 3 measures like this on a single table) and the fact table is big (like 300Million rows big)
I was reading that SUMMARIZE perform really bad with aggregations and It should be replaced with SUMMARIZECOLUMNS.
I wrote this formula
Measure_v2:= AVERAGEX(
SUMMARIZECOLUMNS(
Time_Dimension[Month Name];
FILTER(Time_Dimension;
Time_Dimension[Month Name]<>"LAST"
);
"Count";DISTINCTCOUNT(fact_table[ID])
)
[Count]
)
And it works when I visualize the measure as it is, but when I try to put it in a context (like the table above) it gives me the error "Can't use SUMMARIZECOLUMN and ADDMISSINGITEMS() in this context" How can I make a sustainable optimization from the original SUMMARIZE function?
Before optimizing SUMMARIZE, I would re-visit the overall approach. If your goal is to calculate average fact count per year-month, there is a simpler (and faster) way.
[ID Count]:=CALCULATE(COUNT('fact_table'[ID]),'Time_Dimension'[Last_month] <> "LAST")
[Average ID Count]:=AVERAGEX( VALUES('Time_Dimension'[Year_Month]), [ID Count`])
assuming that:
you have year-month attribute in your time dimension;
IDs in your fact table are unique (and therefore, simple count is
enough)
If this solution does not solve your problem, then please post your data model - it's hard to optimize without knowing the data structure.
On a side note, I would remove ID field from the fact table. It adds no value to the model, and consumes huge amounts of memory. Your objective can be achieved by simply counting rows:
[Fact Count]:=CALCULATE(COUNTROWS('fact_table'),'Time_Dimension'[Last_month] <> "LAST")
How to write this expression in PowerBI
select distinct([date]),Temperature from Device47A8F where Temperature>25
Totally new to PowerBI. Is there any tool that can change the query from sql to PowerBI expression?
I have tried so many type of different type of expressions but getting error, Most of the time I am getting this:
The expression refers to multiple columns. Multiple columns cannot be converted to a scalar value.
Need help, Thanks.
After I posted my answer, wondered if your expected result is get only one date by temperature, In other words, without repeated dates in your result set.
A side note: select distinct([date]),Temperature from Device47A8F where Temperature>25 returns repeated dates since DISTINCT keyword evaluate distinct columns values specified in the SELECT statement, it doesn't return distinct values in a specific column even if you surround it with parenthesis.
Now what brings us here. What I can see in your error is that you are trying to use a table-valued (produces a table with multiple columns) expression in a measure which only accepts scalar-valued (calculate only one value).
Supposing you have a table like this:
Running your SQL query you will get the highlighted in yellow rows:
You can see 01/09/2016 date is repeated. If you want to create a measure you have to define what calculation you want to show for temperature. i.e, average, max or min etc.
In the below expression is being calculated the maximum temperature greater than 25 per date:
MaxTempGreaterThan25 =
CALCULATE ( MAX ( Device47A8F[Temperature] ), Device47A8F[Temperature] > 25 )
In this case the measure MaxTempGreaterThan25 is calculated per date.
If you don't want to produce a measure but a table. In the Power BI Tool bar select Modeling tab and click New Table icon.
Use this expression:
MyTemperatureTable =
FILTER ( Device47A8F, Device47A8F[Temperature] > 25 )
It should produce a new table named MyTemperatureTable like this:
I recommend you learn some basics about DAX, it is pretty different from SQL / T-SQL and there are things you can't do depending on your model and data.
Let me know if this helps.
You probably don't need to write any code if your objective is to show the result in a Power BI visual e.g. a table. Power BI naturally aggregates data if the datatype is numeric (e.g. Temperature).
I would just add a Table visual on a Report page and add the Date and Temperature columns to it. Then in Visualizations / Fields / Values I would click the little down-arrow on the Temperature field and set the Aggregation e.g. Maximum. Then in Visualizations / Fields / Filters I would click the little down-arrow on the Temperature field and set the Filter e.g. is greater than: 25
Hard-coded solutions are unlikely to survive the next question from your users e.g. "but what if I want to see Temperature > 24? Or 20? Or 30?"
I'm building a cube in MS BIDS. I need to create a calculated measure that returns the weighted-average of the rank value weighted by the number of searches. I want this value to be calculated at any level, no matter what dimensions have been applied to break-down the data.
I am trying to do something like the following:
I have one measure called [Rank Search Product] which I want to apply at the lowest level possible and then sum all values of it
IIf([Measures].[Searches] IS NOT NULL, [Measures].[Rank] * [Measures].[Searches], NULL)
And then my weighted average measure uses this:
IIf([Measures].[Rank Search Product] IS NOT NULL AND SUM([Measures].[Searches]) <> 0,
SUM([Measures].[Rank Search Product]) / SUM([Measures].[Searches]),
NULL)
I'm totally new to writing MDX queries and so this is all very confusing to me. The calculation should be
([Rank][0]*[Searches][0] + [Rank][1]*[Searches][1] + [Rank][2]*[Searches][2] ...)
/ SUM([searches])
I've also tried to follow what is explained in this link http://sqlblog.com/blogs/mosha/archive/2005/02/13/performance-of-aggregating-data-from-lower-levels-in-mdx.aspx
Currently loading my data into a pivot table in Excel is return #VALUE! for all calculations of my custom measures.
Please halp!
First of all, you would need an intermediate measure, lets say Rank times Searches, in the cube. The most efficient way to implement this would be to calculate it when processing the measure group. You would extend your fact table by a column e. g. in a view or add a named calculation in the data source view. The SQL expression for this column would be something like Searches * Rank. In the cube definition, you would set the aggregation function of this measure to Sum and make it invisible. Then just define your weighted average as
[Measures].[Rank times Searches] / [Measures].[Searches]
or, to avoid irritating results for zero/null values of searches:
IIf([Measures].[Searches] <> 0, [Measures].[Rank times Searches] / [Measures].[Searches], NULL)
Since Analysis Services 2012 SP1, you can abbreviate the latter to
Divide([Measures].[Rank times Searches], [Measures].[Searches], NULL)
Then the MDX engine will apply everything automatically across all dimensions for you.
In the second expression, the <> 0 test includes a <> null test, as in numerical contexts, NULL is evaluated as zero by MDX - in contrast to SQL.
Finally, as I interpret the link you have in your question, you could leave your measure Rank times Searches on SQL/Data Source View level to be anything, maybe just 0 or null, and would then add the following to your calculation script:
({[Measures].[Rank times Searches]}, Leaves()) = [Measures].[Rank] * [Measures].[Searches];
From my point of view, this solution is not as clear as to directly calculate the value as described above. I would also think it could be slower, at least if you use aggregations for some partitions in your cube.
I have a query to pull clickthrough for a funnel, where if a user hit a page it records as "1", else NULL --
SELECT datestamp
,COUNT(visits) as Visits
,count([QE001]) as firstcount
,count([QE002]) as secondcount
,count([QE004]) as thirdcount
,count([QE006]) as finalcount
,user_type
,user_loc
FROM
dbname.dbo.loggingtable
GROUP BY user_type, user_loc
I want to have a column for each ratio, e.g. firstcount/Visits, secondcount/firstcount, etc. as well as a total (finalcount/Visits).
I know this can be done
in an Excel PivotTable by adding a "calculated field"
in SQL by grouping
in PowerPivot by adding a CalculatedColumn, e.g.
=IFERROR(QueryName[finalcount]/QueryName[Visits],0)
BUT I need give the report consumer the option of slicing by just user_type or just user_loc, etc, and excel will tend to ADD the proportions, which won't work b/c
SUM(A/B) != SUM(A)/SUM(B)
Is there a way in DAX/MDX/PowerPivot to add a calculated column/measure, so that it will be calculated as SUM(finalcount)/SUM(Visits), for any user-defined subset of the data (daterange, user type, location, etc.)?
Yes, via calculated measures. calculated columns are for creating values that you want to see on rows/columns/report header...calculated measures are for creating values that you want to see in the values section of a pivot table and can slice/dice by the columns in the model.
The easiest way would be to create 3 calculated "measures" in the calculation area of the powerpivot sheet.
TotalVisits:=SUM(QueryName[visits])
TotalFinalCount:=SUM(QueryName[finalcount])
TotalFinalCount2VisitsRatio:=[TotalFinalCount]/[TotalVisits]
You can then slice the calculated measure [TotalFinalCount2VisitsRatio] by user_type or just user_loc (or whatever) and the value will be calculated correctly. The difference here is that you are explicitly telling the xVelocity engine to SUM-then-DIVIDE. If you create the calculated column, then the engine thinks you want to DIVIDE-then-SUM.
Also, you don't have to break down the measure into 3 separate measures...it's just good practice. If you're interested in learning more, I'd recommend this book...the author is the PowerPivot/DAX guru and the book is very straightforward.
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)