Parent and Child Functions In Power BI

Parent and Child functions are an important feature in Power BI that enable hierarchical data visualization. In this article, we will explore these functions in detail, along with some examples.

First, let's define what we mean by Parent and Child functions. A Parent function refers to a function that aggregates data at a higher level of a hierarchy, while a Child function drills down into a lower level of detail. In Power BI, we can create hierarchies using multiple columns in a table, and then use the Parent and Child functions to navigate through the hierarchy.

Let's take an example to better understand how these functions work. Consider a sales dataset with columns such as Product, Category, Sub-Category, and Sales Amount. We can create a hierarchy by dragging and dropping these columns in the Fields pane, such that Category is the Parent of Sub-Category, and Product is the Child of Sub-Category.

Once we have created the hierarchy, we can use the Parent and Child functions to navigate through it. For instance, we can use the Drill Up function (a type of Parent function) to aggregate sales data at a higher level of the hierarchy. If we are currently viewing sales data at the Product level, we can use the Drill Up function to see the sales data for all Sub-Categories, or for the entire Category.

Similarly, we can use the Drill Down function (a type of Child function) to drill down into a lower level of the hierarchy. If we are currently viewing sales data for the Category level, we can use the Drill Down function to view sales data for all Sub-Categories under that Category.

Apart from Drill Up and Drill Down, there are several other Parent and Child functions in Power BI that we can use to navigate through a hierarchy. Some examples include Drill To, which allows us to drill down to a specific level of the hierarchy, and Expand All, which expands all levels of the hierarchy to show all data.

Examples of how we can use Parent and Child functions in Power BI:

1. Drill Down: Suppose we have a sales dataset with columns such as Region, Country, City, and Sales Amount. We can create a hierarchy by dragging and dropping these columns in the Fields pane, such that Region is the Parent of Country, and Country is the Parent of City. Once we have created the hierarchy, we can use the Drill Down function to view sales data for a specific City. For example, if we are currently viewing sales data for a Country, we can use the Drill Down function to view sales data for all Cities under that Country.
2. Drill Up: Continuing with the above example, we can use the Drill Up function to view sales data at a higher level of the hierarchy. If we are currently viewing sales data for a City, we can use the Drill Up function to view sales data for all Countries under that Region.
3. Drill To: Suppose we have a dataset with columns such as Year, Quarter, Month, and Sales Amount. We can create a hierarchy by dragging and dropping these columns in the Fields pane, such that Year is the Parent of Quarter, and Quarter is the Parent of Month. Once we have created the hierarchy, we can use the Drill To function to view sales data for a specific Quarter. For example, if we are currently viewing sales data for a Year, we can use the Drill To function to view sales data for a specific Quarter, such as Q3.
4. Related: Suppose we have a sales dataset with columns such as Customer ID, Product ID, and Sales Amount, and a separate customer dataset with columns such as Customer ID and Customer Name. We can use the Related function to access the Customer Name from the customer dataset, based on the common Customer ID column. For example, we can create a visual that displays sales data by Customer Name, even though the Customer Name is stored in a different table.
5. LOOKUPVALUE: Suppose we have a product dataset with columns such as Product ID, Product Name, and Price, and a sales dataset with columns such as Product ID and Sales Amount. We can use the LOOKUPVALUE function to retrieve the Price for a specific Product ID, and then use it in a calculation. For example, we can create a measure that calculates the profit margin for a specific product, by subtracting the cost from the retrieved Price.

In addition to navigating through hierarchies, we can also use Parent and Child functions in other ways. For example, we can use the Related function to access related data from a different table, based on a common column. We can also use the LOOKUPVALUE function to retrieve a value from a table, based on a lookup column and a search value.

In conclusion, Parent and Child functions in Power BI are an essential feature that allow us to navigate through hierarchical data and access related data from different tables. By using these functions effectively, we can create powerful visualizations that reveal insights from our data.