Tableau Joins

In this Tableau tutorial, we learned about Joins in Tableau.

To perform specific analysis, it is frequently essential to merge data from many sources—different tables and even information sources. There must be various ways to merge the tables, depending on the requirements of the information and the objectives of the study.


Tableau Joins are a means to retrieve data from various tables in a database. They allow us to extract data from many tables as long as specific fields are shared between them. For one table, the unique field will be the primary key, while in another, it will be a foreign key. Inner Join, Left Join, Right Join, and Full Outer Join are examples of different types of joins. Tableau makes it simple to do joins. It provides a structured strategy to joining the two tables, as well as a few key options. We may collect data from several tables for evaluation to use the functionality.

One or even more joining elements are used to accomplish a join. Tableau uses the join statement to determine whether variables are matched in between tables as well as how to compare the rows. In the result section, as example, rows with almost the same ID are synchronized.

Difference between Relationship vs joins

Tableau Desktop’s standard method would be to use connections. When integrating data, relationships keep the amount of detail from the source tables. Context-based joins could also be conducted on a sheet-by-sheet approach with connections, giving every input sources more flexibility. In most cases, using relationships to combine data is the best option.

As contrast to a relationship, there could be situations when you really want to create a join explicitly, for either management or for desirable characteristics of a join, including deliberate filtration or repetition.

Challenges Facing in Tableau Joins

Tableau Desktop can make joins and conduct certain basic data structuring, while Tableau Prep Studio is specifically for data preparations. If you need to execute several joins, fix up required fields, alter data structures, perform different pivots, or conduct additional data prep tasks.

  • Users have establish a logical table inside the relationship canvas (the area that see when we just open or establish a data source) and enable the join canvas to inspect, update, or create joins.
  • Tableau information sources that have been uploaded can also be used in joins. One must either update the original data resources to automatically include the joining and use an information blend to merge published data sources.
  • The attributes which we join on must be of the identical data type while connecting tables. The join would crash if we modify the data type after we joined the tables.
  • Without breaching the join, fields used throughout the join statement cannot be eliminated. Instead using Tableau Desktop, employ Tableau Prep Builder to connect data and clean out redundant fields.
  • Tableau Desktop can perform basic data architecture and joins, but Tableau Prep Studio is dedicated to data processing. If we need to run many joins, correct needed fields, change data structures, perform multiple transitions, or undertake other data prep operations.

Creating a Join in Tableau

Suppose we have a collected data. Create a join with two tables, including such Orders and Returns, using Sample-superstore.

  • Select Microsoft Excel from the Data menu, which is located underneath Connection.
  • Then select the Open button after selecting sample-superstore as a data source.
  • Drag the Orders and Returns tables from the information source’s sheets into the data panel. Tableau will then build an automated join between the Ordering and Refunds tables, which could be adjusted subsequently as needed.

Types of Join in Tableau

Tableau allows user to employ four different types of joins: inner, left, right, and full outer. If you’re not sure which join type to employ to merge data from different tables, relationships are a good option.

Inner Join:

When two tables are joined using an inner join, the outcome is a table with entries that correspond in both tables.

Whenever a value does not match in both tables, it is completely ignored.

Left Join:

When you use a left join to merge tables, the outcome is a table that consist all data from the left table as well as matching variables from the right table.

When a value in the left table doesn’t have a corresponding match in the right table, you see a null value in the data grid.

Right Join:

When you use a right join to merge tables, the outcome is a table that contains all variables from the right table as well as matchingvalue from the left table.

When a value in the right table doesn’t have a corresponding match in the left table, you see a null value in the data grid.

Full Outer:

When we merge tables using a full outer join, the outcome is a database that stores all of the data through both tables.

A null value appears in the grid view whenever a variable from one table doesn’t somehow match a variable from the other table.


Union is a technique for merging multiple tables by transferring sets of data through one table to another, although it is not a sort of join. The tables that create union should generally have had the same number of data and column names and different data.

What is Null Value in Join Keys

Joins are normally accomplished at the database server. Many databases deliver information without such entries that contains null values if the columns used to link tables include null values. Tableau, on the other hand, gives an extra option for joining null-valued fields with other null-valued fields for specific single-connection data sources.

Select Data > Join null values to null values once we set up our data appropriate data on the data source screen.

If an option is greyed out, it means that it isn’t accessible for the data source. The join reverted back to the default behaviour is to exclude rows containing null values if we add a second relationship to a data source that implements this option.


Q. What is the difference between join and relationship in Tableau?

Relationships are referred to as the logical layer in Tableau, whereas joins are referred to as the physical layer. Relationships are also not Joins, like we learned in the previous column. Relationships maintain the tables separate rather than combining them into one.

Q. What is default join in Tableau?

Type of joining: Tableau Prep employs an inner join between the databases by default while creating a join.

Q. What is difference between blend and join in Tableau?

Data Blending vs. Data Joining.

The following are the main difference between the two: Data Blending enables the linking of data from many sources whereas Data Joining, on the other hand, simply operates with data from the very same provider.

Q. What is join in data?

When two data sets are integrated side by side in a data join, at least one column from each collected data should be the same.

Q. What is difference between join and data blending?

Data blending acts as a stand-in for a standard left join. The key difference between these two is the timing of the aggregate. A join mixes data before aggregating it. The information is summarized and then combined in a mix.

Q. What is default data blending join?

Data blending refers to the ability to combine data from numerous sources into a single Tableau view without requiring any specific code. A left exterior join is comparable to a standard blending. It is able to approximate left, right, and inner joins by changing whose data source is main or by eliminating nulls.

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