Left Outer Join for Multiple Tables

[sivashankr]

Hi Team,

I do have 4 tables lets say A, B, C and D and my sample SQL statement looks like as shown in SQL#1 below.

I was trying to mimic the same in Power BI using Advanced Editior-->Merging. But I see the different result and the SQL it generates looks like as shown in SQL#2 below.

SQL#1:

SELECT * FROM A

LEFT JOIN B ON A.C1=B.C1

LEFT JOIN C ON A.C2=B.C2

LEFT JOIN D ON A.C3=D.C3

SQL#2:

SELECT * FROM

     (SELECT * FROM

               (SELECT * FROM A

                 LEFT JOIN B ON A.C1=B.C1

                ) AA

        LEFT JOIN C ON AA.C2=B.C2

    ) BB

LEFT JOIN D ON BB.C3=D.C3

[amitchandak]

@sivashankr , refer if these can help

https://radacad.com/append-vs-merge-in-power-bi-and-power-query

https://www.sqlbi.com/articles/from-sql-to-dax-joining-tables/

[parry2k]

@sivashankr seems like A is your fact table and other 3 are dimension table, why not you load all 4 tables in the model and set relationship from A table with other 3 tables.

[sivashankr]

Hello @parry2k 

Thanks for your replay.

Could you please let me know how to create the Left Outer Join in 'relationship' window as it has the cardinality 1-1, 1-M, M-1 and M-M?

[v-zhenbw-msft]

Hi @sivashankr ,

A many-to-one relationship is the most common, default type of relationship. It means the column in a given table can have more than one instance of a value, and the other related table, often know as the lookup table, has only one instance of a value.

And you can refer the following articles.

Power BI – Seven Types of Table Joins

create-and-manage-relationships

Model relationships in Power BI

If you have any question, please kindly ask here and we will try to resolve it.

Best regards,

Community Support Team _ zhenbw

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