Related in Power BI vs. RelatedTable

Attribute	Related in Power BI	RelatedTable
Function	Establishes a relationship between two tables based on a common column	Returns a table that contains all the related rows from a related table
Usage	Used to retrieve related values from a different table	Used to retrieve related rows from a different table
Result	Single value or column	Entire table
Filtering	Filters the related values based on the current row context	Filters the related rows based on the current row context

Introduction

Power BI is a powerful business intelligence tool that allows users to analyze and visualize data in a variety of ways. Two important DAX functions in Power BI are Related and RelatedTable. While both functions are used to establish relationships between tables, they have distinct attributes that make them suitable for different scenarios.

Related Function

The Related function in Power BI is used to retrieve a single related value from a table that is on the "one" side of a one-to-many relationship. This function is commonly used when you want to fetch a specific value from a related table based on a common key. For example, if you have a Sales table and a Products table related by a ProductID column, you can use the Related function to fetch the product name from the Products table for each sale record in the Sales table.

One key attribute of the Related function is that it returns a single value. This means that if there are multiple related values in the related table, the function will return only the first value it encounters. This can be both an advantage and a limitation, depending on the specific use case.

Another important point to note about the Related function is that it can only be used in calculated columns or measures. This means that you cannot directly use the Related function in a visual or slicer. However, you can create a calculated column or measure that uses the Related function and then use that column or measure in your visuals.

Overall, the Related function is a powerful tool for fetching specific related values in Power BI, especially in scenarios where you need to retrieve a single value from a related table.

RelatedTable Function

The RelatedTable function in Power BI is used to retrieve a table of related values from a table that is on the "one" side of a one-to-many relationship. This function is useful when you want to fetch multiple related values from a related table and perform further analysis or calculations on those values. For example, if you have a Customers table and a Sales table related by a CustomerID column, you can use the RelatedTable function to fetch all sales records for each customer in the Customers table.

One key attribute of the RelatedTable function is that it returns a table of values. This allows you to perform additional operations on the related values, such as filtering, summarizing, or aggregating them. This flexibility makes the RelatedTable function a versatile tool for complex data analysis tasks.

Unlike the Related function, the RelatedTable function can be used in both calculated columns/measures and in visuals directly. This means that you can use the RelatedTable function to create dynamic visuals that display related values based on user interactions or filters.

In summary, the RelatedTable function is a valuable function in Power BI for fetching and analyzing multiple related values from a related table. Its ability to return a table of values makes it a versatile tool for complex data analysis tasks.

Comparison

• The Related function returns a single value, while the RelatedTable function returns a table of values.
• The Related function is used to fetch specific related values, while the RelatedTable function is used to fetch multiple related values.
• The Related function can only be used in calculated columns/measures, while the RelatedTable function can be used in both calculated columns/measures and visuals.
• The Related function is suitable for scenarios where you need to retrieve a single value from a related table, while the RelatedTable function is suitable for complex data analysis tasks that involve multiple related values.

Conclusion

Both the Related and RelatedTable functions in Power BI are valuable tools for establishing relationships between tables and fetching related values. The choice between the two functions depends on the specific requirements of your analysis tasks. If you need to fetch a single related value, the Related function is the way to go. However, if you need to fetch and analyze multiple related values, the RelatedTable function is the better option. Understanding the attributes and use cases of these functions will help you make informed decisions when working with related tables in Power BI.