Forum Discussion
Handling null in one-to-many relationship
Hello
I have 2 simple tables with what I would expect to be a 1 to many relationship.
Problem 1
PowerBI however imposes a many-to-many relationship
Here are the table contents, the "Customers" table containing a null value:
How can I avoid powerbi creating a many-to-many relationship?
Problem 2
I created a simple table visual to display the number of tickets per customer.
I would expect Customer A and Customer B to appear, with a count of 0 for Customer A.
PowerBI does not display Customer A at all though
How can I solve that issue?
Many thanks!
PS: a copy of the pbix file here:
Hi, sebastien_druon
#1 The cardinality type selected in relationship depends on the data in the tables("SystemID" contains blank value).If you force a one-to-many relationship between tables, the following error will be reported.
As a workaround, you can change the type of column 'SystemID' from "whole number" to 'Text'.
#2
You need to enable the option "show items with no data" of filed "Data"You can also directly create a new measure 'Count of ticket' to replace the original field"ticket" as below:
Count of ticket = COUNT(Tickets[Ticket])+0Please check my sample pbix file for more details.
Best Regards,
Community Support Team _ Eason
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.
3 Replies
- v-easonf-msft
Community Support
Hi, sebastien_druon
#1 The cardinality type selected in relationship depends on the data in the tables("SystemID" contains blank value).If you force a one-to-many relationship between tables, the following error will be reported.
As a workaround, you can change the type of column 'SystemID' from "whole number" to 'Text'.
#2
You need to enable the option "show items with no data" of filed "Data"You can also directly create a new measure 'Count of ticket' to replace the original field"ticket" as below:
Count of ticket = COUNT(Tickets[Ticket])+0Please check my sample pbix file for more details.
Best Regards,
Community Support Team _ Eason
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly. - Ashish_Mathur
Super User
Hi,
Create a third table which should list down all the unique ID's (without blanks). Now connect the ID columns of the 2 tables to this third table. Create a Many to One relationship wth cardinality of Single.
Was going crazy and creating a new related table with Dax just because it wasn't showing null values.
This info: "You need to enable the option "show items with no data" of filed "Data"" saved my life, thank you so much sir! 🙂
