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When do I need to join tables

I have a more general question on using joins.

The thing is, QV is automatic linking the tables and I can see the connections in the application. So there is the view I need, if I want to see if there is a connection i.e. between a customer and an article I can select either the customer or the article.

Now the question is 'when do I use joins?' I already have the connection without using joins in QV and I am not sure if (or when) it is better to join tables or just to link them.

When are you using joins and when you are avoiding them?

7 Replies
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When do I need to join tables

Hi,

You use joining in QV to load data into another table. So the joining is not a visible joining.

In other BI-software the joining is something that defines sql. After de defining you can than execute a query.

Because of the in-memory technic you use joining to fill-in extra data into tables.

Succes, Halmar

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When do I need to join tables

Thanks. Thats the thing, I can add extra-data to tables but I can also add this extra-data in a second table an link it to the first table. So what would be better, joining the tables or link?

afuchten
Valued Contributor

When do I need to join tables

I use joining only if I really want data of two different tables into one table.

Or when I'm making pre-calculations in the loading in which I need data from more tables in the calculation.

For the overview of normal tables without these pre-calculations I normally don't use the joining, also because of the overview ... where does the data come from? But that's a personal descision.

afuchten
Valued Contributor

When do I need to join tables

If you want a selection to be on both the data it could be better to join them ... 😉

Not applicable

When do I need to join tables

And, if there you want to add a lot of data it's better to link then to join.

But most of the time you want to keep the overview and let the second table in sight.

Not applicable

When do I need to join tables

Thanks a lot, Anita, Halmar, this is helpful.

afuchten
Valued Contributor

When do I need to join tables

You're welcome ... please tag the helpfull answers as helpfull