Difference between Merge Queries Vs Relation Models

[sdasgupta_18]

I am very new to Power BI and wanted to know what exactly is the difference between "merge query" & "relation model” and how to choose between the two. If I have one fact table and one dimension table, and if inner join is the criteria, then I can do it in merge query (in query editor) or I can build a relation model in data view without even using the query editor.

[amitchandak]

Merge Query will create a single table.

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

The relational model is one preferred

https://docs.microsoft.com/en-us/power-bi/guidance/

[sdasgupta_18]

Thanks! So in merge qurries, the output is a single data set, however with a "Direct Query" connection with SQL Server, I believe the join will still be evaluated at the SQL side and no data set will be loaded in Power BI. Please correct if I am wrong. So in both the cases, we are doing the same thing.

[v-kelly-msft · Accepted solution]

Hi @sdasgupta_18 ,

I'm afraid that you have misunderstood about Merge Queries and Relation Models,in a sense,they have reached a similar result that they have created a relationship between 2 tables,but essentially,"merge queries" is to modify the original table to a new one by combing other columns from another table,while "Relation Models" is just creating a relationship between 2 tables,and nothing is changed inside the tables.

As for "Direct query",although it doesnt load data to Power Bi,but when you use"merge queries",it will first send queries to SQL database in order to get data you need then do the merge option in power bi,so such option isnt done at the SQL side but in power bi ,as you will find ,after merging,a new table is existing in desktop under "direct query" mode.

Best Regards,
Kelly

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[sdasgupta_18]

Thanks a lot Kelly....this is really useful 🙂