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Tableau | Data prep | Data visualisation

Tableau Data Model: Relationship calculations

Relationships landed in 2020.2, but now in 2020.3 you can finally build them with calculations.

Tim Ngwena •12 August 2020 •1 min read •4 min watch •4.2K

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Relationships arrived in Tableau 2020.2, but the ability to define them with calculations was only added in 2020.3
To create a relationship calculation, drag a table to relate it and pick the relationship calculation option at the bottom of the field matching dialog
You can concatenate two string fields, such as Book ID 1 plus Book ID 2, to form a single matching key for the relationship
This removes the need for the older workaround of using join calculations inside a relationship to bring fields together
Once set up, Tableau pulls related fields together dynamically across the data model

0:00In 2020.3, Tableau have added relationship

0:06calculations to the feature set. Now,

0:09relationships

0:09were a new feature in 2020.2, but back then

0:12, you couldn't do calculations to form

0:15relationships,

0:16but now you can. Let me show you how that

0:18works. It's going to be a very, very quick

0:19video. I'm going to go ahead and connect to

0:22the same beta Bookshop data source that I

0:24connected to in my previous tutorial. Be

0:26sure to check that video out. It's the

0:27exact same

0:28data source, so you can just go ahead and

0:30grab the file from that video. I'll also

0:32put

0:32a link in the description below to that

0:34data set. Now, here, what we have is

0:37essentially

0:38a very simple data set where we have the

0:40authors. And what we did in the previous

0:42version is

0:42we essentially connected the authors to the

0:44books, and the relationship there is based

0:46on the author ID. So you can see here that

0:49Tableau automatically figured that out. Now

0:51,

0:51the issue we had before is that if we

0:53wanted to bring the book information, I'll

0:55just show

0:55you here. You will see that I actually

0:58created an artificial field to showcase how

1:01to do

1:02joins inside of the relationship in order

1:04to bring the information in, if that makes

1:07sense. So Book ID 1 and Book ID 2 basically

1:11come together to make the book ID. And so

1:14before what I had to do is I had to open up

1:16the author, open up this information here,

1:19then go in here and do a join calc, which

1:22is available prior to 2020.2. So I'm just

1:26going to close this because that's not what

1:27I want to do. I actually want to go ahead

1:29and remove this entirely. So if I actually

1:32just go back and then close this connection

1:36,

1:36and I'm going to grab the info, and I'm

1:38just going to drop it here next to Book

1:39because

1:40this is the information about the book

1:42itself. So I'll drop this here, and you'll

1:44see that

1:45it automatically picks the right column, of

1:47course, but I don't want to do that. I want

1:48to showcase the new relationship

1:50calculation. So you can see here at the

1:53very bottom is

1:53this new option for relationship

1:55calculations. Let me just highlight that

1:58for you here. It's

1:59just here at the very, very bottom. And so

2:02if you actually click on that, you get the

2:04same calculation window that we used to.

2:07Just make this larger so you can see. Let's

2:09also

2:10just type in Book ID, if I can spell

2:12correctly, Book ID 1 plus Book ID 2. And

2:15the reason I'm

2:16adding these together is because they're

2:18two strings, so I'm essentially concaten

2:20ating

2:20them together to make the actual Book ID.

2:23So click Apply and click OK, and we're done

2:27.

2:28And that's pretty much it. That's

2:29everything set up the way we'd need to. And

2:32now we can,

2:32of course, go over to Sheet 1 and start

2:34working with it as we did before. I can

2:37grab an author,

2:39grab their first name and last name, then

2:43grab a book. Let's grab the title and we

2:46can

2:46get the information about that book and

2:48Tableau is pulling all of that information

2:50dynamically

2:51together. And that's pretty much it. It's a

2:53really simple feature, but it's something

2:55that a lot of people have asked for in the

2:57previous version of relationships that was

3:00released in 2022.2. And it also gives us a

3:03hint that Tableau is not done yet. They

3:05might

3:05be still adding more features into this

3:07toolset. So if you're watching this, maybe

3:09a couple

3:09of years down the line, I'm sure there's

3:11plenty more about this feature. So be sure

3:13to subscribe

3:14to the channel, check out some of the other

3:17videos on this channel about that. And

3:18while

3:18you're here, why not check out some of the

3:20other videos on 2020.3. And by all means,

3:23let us know if you like the content, like,

3:25comment, dislike, whatever it is, let us

3:27know,

3:27and we'll try and improve the quality of

3:28what we're producing.

Rollup

Tableau 2020.3 lets you define a relationship between two tables using a calculation, rather than only a direct field match, so you can build a matching key on the fly instead of pre-processing your data.

Built on a simple data source with authors and books, where the books table splits its ID across two string fields that need combining before they can match the authors table.

The Breakdown

Recap: basic relationships from 2020.2 0:40

Tableau can automatically detect and relate tables when a shared field, such as an ID, already matches cleanly between them.
The old workaround: join calcs inside a relationship 1:02

Before 2020.3, if the fields you needed to match didn't line up directly, you had to open the relationship and use a join calculation to bring the data together — an extra, fiddly step.
Remove the artificial workaround field 1:23

If you'd built a field purely to force a match under the old method, you can now get rid of it since it's no longer needed.
Drag in the table you want to relate 1:40

Drop the second table next to the first as normal; Tableau will attempt to auto-match fields, but you don't have to accept its default guess.
Write a calculation to build the matching key 2:02

In the calculation editor, concatenate the two string fields (for example Book ID 1 plus Book ID 2) to construct a single key that matches the other table, then apply and confirm.
Use the related data as normal 2:20

Once set up, you can drag fields from either table onto a sheet and Tableau pulls the related information together dynamically, exactly as with a standard relationship.

Worth Knowing

Relationships themselves were introduced in 2020.2; the ability to define them via calculation is new in 2020.3, so this only works on that version or later.
This removes the need for the older join-calculation workaround inside relationships, which required opening and editing the relationship directly.

Use It When

Reach for this when the fields you need to relate two tables on don't already match directly — for example when an ID is split across multiple columns or needs formatting to line up.

How this Rollup was made provenance & method

A Rollup is drafted by AI from the video's transcript, then reviewed and edited by Tim. Everything used to produce this one is listed below — the model, the exact prompt, and the source video — so the process is transparent and reproducible.

Transcription: On-device — NVIDIA Parakeet v3 for recent videos, OpenAI Whisper large-v3 for earlier ones. The transcript never leaves the machine or gets published.
Drafting: Claude Sonnet 5 in the cloud, from that transcript.
Prompt: The exact Rollup prompt (v2) — the full system prompt, unedited.
Source video: Watch on YouTube
Drafted: 5 July 2026 at 09:38
Reviewed & edited: 5 July 2026 at 09:41 · by Tim Ngwena

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