Forum Discussion
DAX Measure evaulation context issue with related table
Hi all, I'm having an issue with a Measure when I introduce data from a related table, so let me explain (the second time, after losing my first post):
I have a Usage table with usernames and total hours used:
| Username | Total Hours |
| Jane | 20 |
| Joe | 50 |
| Sally | 10 |
| Jeff | 20 |
I have a simple measure that calculates the Totals Hours as a percentage of the grand total:
Hrs % of GT = DIVIDE([Total Hours], CALCULATE([Total Hours], ALLSELECTED(Usage)))
I have another Users table that has some information about the users, for instance their office, related to the Usage table by [Username] Cross Filter Direction is single from Users to Usage:
| Username | Office |
| Jane | Boston |
| Joe | New York |
| Sally | New York |
| Jeff | Boston |
The result is I can create a simple Table or Matrix visual that I can Slice on, and get something like this:
| Office | Username | Total Hours | Hrs % of GT |
| New York | Joe | 50 | 83% |
| New York | Sally | 10 | 17% |
I have another table Transactions, that I Filter/Slice to a single row, that looks like this:
| Product | Cost |
| ProductName | $100 |
I created a simple measure that sums the Cost column, in the case of the filtering and slicing that measure returns the single value:
Sum of Transactions = SUM(Transactions[Cost])
Lastly I created a third measure called distributed cost:
| Username | Total Hours | Hrs % of GT | Distributed Cost |
| Jane | 20 | 20% | $20 |
| Joe | 50 | 50% | $50 |
| Sally | 10 | 10% | $10 |
| Jeff | 20 | 20% | $20 |
The problem comes, when I attempt to introduce Office to the Table (or Matrix) I lose the Disitrubuted Cost values. What is particulary strange is I don't lose all the values, only sum and the Grand Total for the column remains correct. The ultimate goal in all of this is to filter the above table/matrix on for example: Hrs % GT greater than 10%
And have the measure re-compute to evenly distribute the cost based on the new GT, so that it might look like this:
| Office | Total Hours | Hrs % of GT | Distributed Cost |
| Boston | 40 | 45% | $45 |
| New York | 50 | 55% | $55 |
| Total | 90 | 100% | $100 |
It seems like this should work, because I want the measures to respect the filter/sliced context, but I don't understand why I'm seeing the behavior I'm seeing when I introduce the related data of Office, particularly since the Hrs % of GT measure works properly. What am I missing; do I need to do something with 'Related' for the cost disitribution measure to work properly? Something with applying the proper filter context?
Thank you!
Hello all,
I think, after building a "clean" test model I've discovered the issue at hand. I have a many-to-many relationship which is causing the issue I'm seeing. My clean model has only many-to-single relationships. This would seem to make sense to me based on what I'm seeing. Based on what I've described does this make sense to everyone?
15 Replies
- edhans
Community Champion
A visual of your model would help. I may have missed it but didn't see how you are relating Transactions to the rest of the model, but I suspect it is not filtering the rest of the model. Meaning, whatever you are relating Transactions to, Transactions is the Many of a One to Many.
If that is correct, see what happens if you modify this measure:
Distributed Cost = [Sum of Transactions] * [Hrs % of GT]Change it to this:
Distributed Cost = CALCULATE( [Sum of Transactions] * [Hrs % of GT], CROSSFILTER ( Transactions[SomeField], TheOtherTable[KeyField], BOTH ) )What CROSSFILTER() does inside of CALCULATE is turns a single directional filter to bi-directional for that measure only, which is what you want. You can turn on bi-directional in the relationship itself, but that should be avoided at all costs as it can introduce unexpected issues or simply break things as the model gets more complex.
If that is not helpful, please post a pic of your model from the model view and how Transactions is related to another table.
Hi,
Thanks for the quick response. At the moment there is no relationship between the Transactions table and the Usage and other associated tables. The reason being I brought the Transactions table in to explicitly slice down to a single transaction, and use its value as a constant for the distirbution calculations. In the future I might want to slice to a new transaction and then re-calculate a new disitrubtion based on new usage data.
I could create a relationship between the Usage data and the Transactions based on "Product" if you think that might help? I assumed that since I was basically using the value as a constant a relationship wasn't neccessary, but perhaps it is?
- edhans
Anonymous wrote:Hi,
Thanks for the quick response. At the moment there is no relationship between the Transactions table and the Usage and other associated tables. The reason being I brought the Transactions table in to explicitly slice down to a single transaction, and use its value as a constant for the distirbution calculations. In the future I might want to slice to a new transaction and then re-calculate a new disitrubtion based on new usage data.
I could create a relationship between the Usage data and the Transactions based on "Product" if you think that might help? I assumed that since I was basically using the value as a constant a relationship wasn't neccessary, but perhaps it is?
Then I'm confused. You cannot filter anything with a disconnected table via a slicer, and to use it with measures you have to use measures like TREATAS() to create a virtual relationship. Again, I'd need to see a more compressive model of what you have and are trying to accomplish.
- amitchandak
Super User
Try new measures like
Sum of Usage = calculate(SUM(Usage[Total Hours]),all(Users)) Hrs % of GT = DIVIDE(sum(Usage[Total Hours]), [Sum of Usage ]) Distributed Cost = var _cost = maxx(product,product[Cost]) return [Hrs % of GT] * _costAs join between user and usages has been assumed on usename /id
Appreciate your Kudos. In case, this is the solution you are looking for, mark it as the Solution. In case it does not help, please provide additional information and mark me with @
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I just assumed the relationship between the first two tables in your list having username.
If possible please share a sample pbix file after removing sensitive information.Thanks.
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Hello all,
I think, after building a "clean" test model I've discovered the issue at hand. I have a many-to-many relationship which is causing the issue I'm seeing. My clean model has only many-to-single relationships. This would seem to make sense to me based on what I'm seeing. Based on what I've described does this make sense to everyone?
- edhans
Yup. In general many-to-many should be avoided unless you know exactly how it will work and there is no other way. Glad you found the issue and were able to get it to a one-to-many relationship.
if only it were that simple... my "clean" model was for the purposes of troubleshooting and to post here. The real model retains the many to many and I know why it's there and what the underlying issues are, but "fixing" it becomes its own project unto itself. This was just a fall on effect that I didn't recgonize right away.
Joy...
Thanks all!
