Today’s article focuses on Data joining in Tableau. In Tableau, when we work with enormous data sets, it is common to find that those data sets have multiple tables with different data fields. This tells us data usually don’t reside in a single table. We can have many different tables. It means we can join tables using columns that are common or related. These related fields are usually known as Key fields or records.

The method of combining this data is referred to as Data Joining. We can combine tables based on the same or different data sources to create a single table.

Let’s look at the different types of Joins we have in Tableau.

Types Of Joins

• Inner Join
• Left Join
• Right Join
• Full Outer Join

We’ll look at each of these joins and demonstrate with the Sample superstore dataset in our Tableau Desktop.

Inner Join

What is an inner data join?

Inner Join in Tableau refers to how we can create a new table from two tables containing only values or columns common between these two tables.

Let’s look at our demonstration below in Tableau Desktop.

We will bring in our Superstore data, load it in the Data pane, and then do an inner join using the order ID from the Orders table and the OrderID Returns table. Let’s see the image below.

Left Join

Left join tableau is also a way of creating a new table that is formed from all data from the left table and only matching values from the right table. If there are no common rows in the right table, null values are returned in the new table.

Let’s demonstrate this join in Tableau. We’ll still use the Orders table and Returns table in our superstore dataset. The image below shows how we did that. In the data view below, let’s also observe null data present in some of our columns.

Right Join

Right Join is formed in Tableau between two tables, whereby the resulting table or new table created contains all values of the right table and only matching values from the left table. For non-common rows, null values are returned.

Look at the screenshot below to see our Right Data Join in Tableau.

Full Outer Join

The full outer join is a type of join formed between two tables, whereby the resulting table contains all the data values from both the left and right tables. Also, values that do not find a match in both tables are shown as null.

A screenshot of how to perform a Full Outer Join is shown below;