Custom table calculation scope in Tableau - Cell-by-Cell Formula Trace

Sample Data

Sales data by Region and Category

Cell	Value
A1	Region
B1	Category
C1	Sales
A2	East
B2	Furniture
C2	100
A3	East
B3	Office Supplies
C3	150
A4	East
B4	Technology
C4	200
A5	West
B5	Furniture
C5	120
A6	West
B6	Office Supplies
C6	180
A7	West
B7	Technology
C7	220

Formula Trace

WINDOW_SUM(SUM([Sales]))

Step 1: SUM([Sales]) for each row

Step 2: WINDOW_SUM(SUM([Sales])) over entire table

Step 3: WINDOW_SUM(SUM([Sales])) partitioned by Region

Step 4: WINDOW_SUM(SUM([Sales])) partitioned by Region and Category

Cell Reference Map

    A       B               C
1 |Region | Category      | Sales
2 | East  | Furniture    | 100  
3 | East  | Office Supplies | 150  
4 | East  | Technology   | 200  
5 | West  | Furniture    | 120  
6 | West  | Office Supplies | 180  
7 | West  | Technology   | 220  

Arrows: WINDOW_SUM uses SUM([Sales]) from column C
Partitions can be by column A (Region) or columns A+B (Region+Category)

Cells referenced are the Sales values in column C, grouped by Region and Category in columns A and B

Result

    A       B               C       D
1 |Region | Category      | Sales | Window Sum
2 | East  | Furniture    | 100   | 450
3 | East  | Office Supplies | 150   | 450
4 | East  | Technology   | 200   | 450
5 | West  | Furniture    | 120   | 520
6 | West  | Office Supplies | 180   | 520
7 | West  | Technology   | 220   | 520

Column D shows WINDOW_SUM(SUM([Sales])) partitioned by Region, summing sales within each Region group

Sheet Trace Quiz - 3 Questions

What does WINDOW_SUM(SUM([Sales])) calculate when no partition is set?

A Sum of all sales in the entire table

B Sum of sales per Region

C Sum of sales per Category

D Sum of sales per row

Key Result

WINDOW_SUM aggregates SUM([Measure]) over a defined partition or entire table