Forum Discussion
Joins in SQL vs using relationships performance
Anonymous ,
The answer depends on how you want to shap your data model. Best Practice is a Fact Table (contains the items that you want to summate, count, etc), and a few Dimension tables (ones that will help you filter the fact table).
If your PBI data model requires the two SQL tables to be in one table, then join on loading via the SQL script. Or if you access to the SQL DB, create a View that joins them, then you can just load the view into PBI.
Also, as v-diye-msft said, the Relationships in PBI act in certain ways. This may not be in the way you need for your model, as the relationships are filter relationships not joins.
hope that helps.
Hi Anonymous
When we load two or more tables at the same time, Power BI desktop will look at column names in the tables we are querying to determine if there are any potential relationships. If there are, those relationships are created automatically.
From Cardinality and Result we can get:
many : many -> Inner
one : one -> Full Outer
one : many -> RightOuter
many : one -> LeftOuter
if the relationships set by SQL DB is the same as Power BI detect, then you needn't modify them. While the logic is different, you can manage relationships follow this article based on your needs. See: Create and manage relationships in Power BI Desktop.
Here's similar thread could also be your reference:
https://community.powerbi.com/t5/Desktop/Relationships/m-p/233398