Update data in query without deleting the old data

[TSunami61]

My query is connected to a source which is updated automaticlly every day. My problem is that I need the history data, too.

For example:
Data in source of 08/02/2016: a
Data in source of 09/02/2016: b

Now:
Data in query of 08/02/2016: a
Data in query of 09/02/2016: b

What I want:
Data in query of 08/02/2016: a
Data in query of 09/02/2016: a + b

How can I build a query which saves the history data?


I hope that anybody can help me.
Thank you for your help.

TSunami61

 

[ImkeF]

You can do that by appending the new data to the current output. This is a self-referencing append-operation, have a look at the example file:
https://www.dropbox.com/s/hmbfnvy9hyc84yz/ME_PQCreateLoadHistory.xlsx?dl=0

It also contains a mechanism that will prevent unintended double appends (so currently, all double appends at one day will be deleted by a removing duplicates-step)

 

[ImkeF]

If you're having problems setting this up for your own data, this article might help:
How to create a Load History or Load Log in Power Query or Power BI – The BIccountant