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greglauder Frequent Visitor
Frequent Visitor

One of the columns must have unique values



I'm having trouble merging information into one table on power BI. 


I have 3 tables which I work from which I work from


1. Policy

2. Motor Drivers

3. Motor Vehicles


They all have a common field which is the unique policy reference number e.g. GREG-1001. I've managed to create the following 2 relationships:


  • Policy & Motor Drivers
  • Policy & Motor Vehicles

However when I try to create a relationship between Motor Driver & Motor Vehicle it comes up with the an error message stating "Can´t create a relationship between two columns because one of the columns must have unique values"


In the motor drivers column there can be more than one row per unique reference number if there is more than one driver.


Can anyone help regarding this?





Community Support Team
Community Support Team

Re: One of the columns must have unique values

Hi @greglauder,


For your description, I think you tables contains duplicate records, right?

If this is a case, you need to create new table with union distinct policy records.
After these steps, you can create relationships between new 'unique policy' table and original drivers/vehicles tables.


If above not help. please share some sample data for test.



Xiaoxin Sheng

Community Support Team _ Xiaoxin Sheng
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IvanMilev Frequent Visitor
Frequent Visitor

Re: One of the columns must have unique values

This was very helpful to me ! Thanks!