Merge and Merge VS new

[PBILover]

I have a table from  Source 1, and another detail table from Source 2 in a power BI. In my case  1 row from the table one can have multiple rows in second table.(Primary key - foreign key relationship). I want to combine the data from both the tables as below

Id -Table 1	Channel- Table 1	Id -Table 2	Type-Table 2	Time
1	Email	1	Processed	12/04 2.03:00
		1	delivered	12/04 2.03:05

So my question is shall I use Merge or Merge as new option . As both tables will have millions of records , which approach will be good ? how to avoid duplicate data loading in power BI?

How Merge Vs Merge as new in a power BI works?

Thank you very much in advance .

[v-shex-msft · Accepted solution]

Hi @PBILover,

According to your data amount, I do not so recommend you to merge these tables. (they should affect the performance)
You can consider extracting the key fields from two tables as the bridge to link them. Then you can use header table and detail table fields to create data visualizations without any merger operations.

How to Join Many to Many with a Bridge Table in Power BI 

In addition, you can also try to join functions if you needed.

From SQL to DAX: Joining Tables 

Merge Vs. Append In Power BI In Power Query Editor 
Regards,

Xiaoxin Sheng