Fridge Sales Summary by Region

/* 
Calculate the sum of sales for each region where the product category 
is 'Fridge' and the description is 'Small'.

Returns a table with regions and respective sales.

Parameters:
    None (usually context is provided by the data model itself)

Returns:
    Table with columns: Region and SumOfSales
    
Exceptions:
    This function assumes that the data model contains 'Sales', 'Region', 'Category', and 'Description' columns.
*/

SUM_OF_SALES_BY_REGION := 
SUMMARIZECOLUMNS(
    'Sales'[Region],                       -- Group by Region
    FILTER(
        'Sales', 
        'Sales'[Category] = "Fridge" &&    -- Category filter: Fridge
        'Sales'[Description] = "Small"     -- Description filter: Small
    ),
    "SumOfSales", SUM('Sales'[SaleAmount]) -- Sum the sales amount per group
)

-- Sample usage in a Power BI report:
-- Add a table visualization and use this measure
-- as the data source to summarize the sales.

Explanation

1. Preparation

Ensure your data model has the relevant columns:

• Sales table with Region, Category, Description, and SaleAmount columns.

2. Function Definition

In this DAX function:

• SUMMARIZECOLUMNS: This function creates a summary of the data with specific group by columns and measures.
• FILTER: Applied to filter only rows where Category equals 'Fridge' and Description equals 'Small'.
• SUM('Sales'[SaleAmount]): Aggregates the sales amount of filtered data.

3. Commenting and Documentation

• Inline comments are added to articulate the logic of filtering and aggregation.
• The docstring at the top provides information about function parameters, return type, and assumptions.

Usage Example

1. Open Power BI Desktop: Ensure your data model has the relevant Sales table.

2. Create a New Measure:

   • Go to the Modeling tab.
   • Click on 'New Measure' and paste the above DAX code.

3. Visualize the Measure:

   • Add a table visualization.
   • Drag fields Region and the newly created measure SumOfSales onto the table.

This will provide you with a summarized table displaying the sum of sales for 'Fridge' products with a 'Small' description grouped by region.

Points to Remember:

• The code snippet assumes that the necessary columns are present in the Sales table.
• Always validate the input data to ensure consistency and correctness.
• Ensure good practices by making sure the DAX code is efficient and can handle large datasets.

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