In Tableau, you can calculate the difference between values in the same column, grouped by another column, by using Table Calculations. Here’s how you can achieve this:
Steps to Calculate Row Difference in Tableau:
1. Drag your data fields to the canvas:
• Place the grouping column (e.g., Category) in the Rows or Columns shelf.
• Place the measure column (e.g., Sales) in the Columns or Rows shelf.
2. Add a Table Calculation for Difference:
• Right-click on the measure (Sales) and select Quick Table Calculation > Difference.
• This will calculate the difference between consecutive rows of the same column.
3. Customize the Table Calculation:
• Right-click on the measure again, select Edit Table Calculation.
• Under “Compute Using,” choose how the difference should be calculated:
• If your data is grouped by a column, choose Specific Dimensions and ensure only the grouping column (e.g., Category) is selected.
• This ensures the calculation restarts for each group.
4. Sort Data Appropriately:
• Ensure the rows are sorted correctly for the difference to make sense. For example, if calculating the difference by date, sort by the date field in ascending order.
Example
Category Date Sales Difference
A 2024-12-01 100 -
A 2024-12-02 150 50
A 2024-12-03 200 50
B 2024-12-01 300 -
B 2024-12-02 250 -50
• Group by Category.
• Compute difference on Sales.
If you want a custom calculation without Table Calculations, you can write a calculated field using LOD (Level of Detail) or Window functions. Let me know if you’d like help with that!