How do I join two tables in Superset ? I need to combine the result in order to visualize the data

[ghost]

How do I join two tables in Superset ? I need to combine the result in order to visualize the data

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[suddjian]

You can use SQL Lab (+new button > SQL Query) to write any sql you want, and then hit the "Explore" button to make a chart from your query.

[mistercrunch]

You may also want to create a view a view in your database and use this view as a datasource. It's effectively the same as the solution above, except the view is stored in the database and can/could be reused outside of Superset

[barmic12]

I'm not sure that I understand SQL Lab View correctly. It doesn't create SQL view, right? I checked that in my database, but I didn't find them.
So, why don't you mention about SQL Lab View in FAQ?
https://superset.incubator.apache.org/faq.html#can-i-query-join-multiple-tables-at-one-time

It took me a long time to discover that with a button Vizualize I can create graph from multiple tables. Before that I was sure that I had to create views in SQL to achieve this.

[ghost]

Yes It doesnt create sql view.!!

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On Tue, Nov 26, 2019 at 8:46 PM Bartek Michalak ***@***.***> wrote: I'm not sure that I understand SQL Lab View correctly. It doesn't create SQL view, right? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#8645>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AL5J2MPLMUQNNVDYL3YTELTQVU4VBANCNFSM4JRIW57Q> .

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[mistercrunch]

The "Explore" button in SQL Lab is effectively creating a Superset-managed view. The "datasource" object that gets created stores that SQL in its definition, and runs queries against it the same way that it would against a table, but as a subquery.

We did a lot of design work as part of SIP-34 that should make this flow much more clear.

[ManZzup]

Is this still open? like to work on this since it aligns with a current requirement we are having

[thunderbird57]

Is this still open? like to work on this since it aligns with a current requirement we are having

I don't think we need to do something here. There are 2 options

• 1 Join in SQL Lab - It will be stored in Superset internal database and the view will not be available outside Superset.
• 2 Create a view in source database by joining those tables and use the view inside Superset

Number 2 is preffered option mostly as it pushes data prep to Database itself and make it available for other BI platforms too.

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[linganmm]

Can the 2nd option be done with superset? Or does the user have to log on the backend database and create a view on it?

[asemprini]

So... if I have a fact table with dimensions, I have to create a super view with all the fields I will be using? It's the only way?

[m-ocean-it]

@linganmm:

Can the 2nd option be done with superset? Or does the user have to log on the backend database and create a view on it?

You can do that right from Superset! You just need to make sure the "Allow CREATE VIEW AS" is enabled for that specific database.

[ttauzo]

it is still not an efficient solution because:

1. you should be able to join by click all fact and dimension tables bases on relationships (why to use sql for sth that can be clickable in a tool for business users)
2. still if you join all tables you can apply filter either:

• on technical ids that use db index but are not understandable for business user or
• on "business name" but then supserset will run a query with condition on a column without index (you would have to duplicate indexes and have indexes on both technical and business columns which is waste of resources)
  Techncial and business "layer" should be separated

[mistercrunch]

This write up explains a bit more where Superset stands:
https://preset.io/blog/dataset-centric-visualization/

[rusackas]

I'll add that there are many tools and techniques to do this lower in the stack, including semantic layers like Cube or DB-like tools such as Trino. It might also be worth mentioning here that Superset does have an experimental in-memory "meta database" that one can use to join... but I wouldn't use it on large joins... it's more for lighter tasks like CSV-driven workflows.