Question

How can I combine two unrelated tables in a way that allows for cross-filtering in Power BI?
I need a solution in Power BI to enable cross-filtering between two tables that lack a direct relationship. The approach should dynamically handle scenarios where user-applied filters affect the data in both tables. What is the best approach using DAX functions like TREATAS, CROSSFILTER, or bridge tables to ensure accurate filtering across unrelated tables?

Answer 1

Cross-filter an unrelated table with another table in Power BI. The DAX functions used are TREATS or CROSSFILTER, and another option is to create a bridge table. All of these methods give the correct filtering when direct relationships do not exist.

The first approach: Bridge Table:

Create a Bridge Table:

Create a unique list of all possible bridging keys to serve as a bridge table if both of the two tables share the same common key (ProductID in Sales and Inventory tables).

Here is how to create a new table in Power BI using DAX:

BridgeTable = DISTINCT(UNION(VALUES(Sales[ProductID]), VALUES(Inventory[ProductID])))

• Establish Relationships:

  • Connect the Bridge Table to both original tables using a one-to-many relationship.

  • Ensure "Both" cross-filter direction is enabled.

• Enable Cross-Filtering:

  • Applying filters on the Bridge Table now impacts both tables.

Approach 2: Using TREATAS for Dynamic Filtering

1. Create a Measure:

   • Use TREATAS to apply dynamic filtering without explicit relationships.

   • Example:

Filtered Sales = 
CALCULATE(
    SUM(Sales[Amount]),
    TREATAS(VALUES(Inventory[ProductID]), Sales[ProductID])
)

1. Dynamic Behavior:

   • The measure evaluates the Inventory table’s filters on the Sales table.

   • Cross-filtering works without a relationship.

Approach 3: Using CROSSFILTER for Relationship Control

1. Direct Relationship Adjustment:

   • If a relationship exists but filtering is not working correctly, use CROSSFILTER to control filter directions.

   • Example:

CrossFiltered Sales = 
CALCULATE(
    SUM(Sales[Amount]),
    CROSSFILTER(Sales[ProductID], Inventory[ProductID], Both)
)

1. Resolve Filter Issues:

   • Ensures bidirectional filtering when needed.