Union and join basics in Tableau - Dashboard Guide

Dashboard Mode - Union and join basics

Business Question

How can we combine sales data from two different regions to see total sales and compare product performance across both?

Sample Data

Sales_North

OrderID	Product	Sales
101	Widget	100
102	Gadget	150
103	Doohickey	200

Sales_South

OrderID	Product	Sales
201	Widget	120
202	Gadget	130
203	Thingamajig	180

Dashboard Components

• KPI Card: Total Sales Combined
  Formula: SUM([Sales]) after union of both tables
  Result: 880 (100+150+200+120+130+180)
• Bar Chart: Sales by Product
  Data: Union of Sales_North and Sales_South
  Aggregation: SUM(Sales) grouped by Product
  Shows total sales per product across both regions:
  - Widget: 220
  - Gadget: 280
  - Doohickey: 200
  - Thingamajig: 180
• Table: Joined Data on Product
  Join Type: Full Outer Join Sales_North to Sales_South on Product
  Columns:
  - Product
  - Sales_North (Sales from North region)
  - Sales_South (Sales from South region)
  Example rows:
  Widget | 100 | 120
  Gadget | 150 | 130
  Doohickey | 200 | NULL
  Thingamajig | NULL | 180

Dashboard Layout

+----------------------+--------------------------+
|  KPI: Total Sales    |  Bar Chart: Sales by     |
|  Combined (880)      |  Product                 |
+----------------------+--------------------------+
|          Table: Joined Data on Product           |
|  (Product, Sales_North, Sales_South)             |
+--------------------------------------------------+

Interactivity

A filter on Product lets users select one or more products. When filtered:

• The KPI card updates total sales for selected products only.
• The bar chart shows sales bars only for selected products.
• The joined table shows sales data only for selected products, with NULLs where data is missing.

This helps compare sales across regions for chosen products.

Self Check

If you add a filter to show only Product = 'Widget', which components update and what results do they show?

• KPI Card: Shows total sales 220 (100 North + 120 South)
• Bar Chart: Shows one bar for Widget with height 220
• Joined Table: Shows one row:
  Widget | 100 | 120

Key Result

Dashboard combining sales data from two regions using union and join to compare total and product-level sales.