Tableau >> Intermediate (4) Using Unions to Combine Data

Using Unions to Combine Data

• 1. Concept
• 2. Union Your Data
• 3. Create a Union Manually
• 4. Merge Mismatched Fields

1. Concept

A union is way to connect multiple tables from a single data source.

It combines rows from two or more tables to lengthen the scope of your data.

2. Union Your Data

The tables that you combine using a union must have the same structure:

• same number of fields
• related fields must have matching field names and data types

After the data union,

• all the rows are included in the union, even the duplicate values
• two new columns(Sheet & Table Name) will be automatically generated

3. Create a Union Manually

Two ways to create a union:

1. drag and drop

   • clicking and dragging the first sheet to the empty canvas
   • click and drag the second sheet underneath the first sheet until the [Union] box appears
   • drop the second sheet when the box changes to a solid orange color
   

2. Use [New Union] option

   • double-click the New Union option

     

   1. Specific (manual):

      create unions manually by selecting specific files that are imported in the Data Source page.

   2. Wildcard (automatic):

      created automatically by searching for files through a directory

4. Merge Mismatched Fields

For duplicate fields with mismatched field names but the same values, we can combine them by using Merge Mismatched Fields

Process:

1. Go to the [Data Source] page
2. Select the fields we want to merge
3. From the drop-down menu, click [Merge Mismatched Fields]
4. Rename the merged field