Query folding to improve Power BI performance

Query Folding allows Power Query to push some of the transformations back to the database and that way query and return the data more efficiently.
Let's go into more detail in this video.

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[MrNillock]

This is one of my favorite tricks!!! get the servers to do the work for you :)

I know that SQL will auto FOLD for most simple functions however it will not for joins... BUT if you know a little SQL you can construct an SQL statement that joints/merges or more complex statements and get HUGE performance improvements... I like to get SQL to do most of my heavy lifting :)

[eleftheriakoniari]

Great tips! Which sources allows query folding? I have only read rights to organisation sql server will this be a problem for query folding?

[learnspreadsheets]

I’m a little bit confused. 3 questions: 1. does this mean that query folding happens automatically or does it need to “switched on” somehow 2. Once you do a “non folding” step (like merge columns), all subsequent steps would be not folded, is that right? 3. I normally get data from excel (and sometimes from web/Facebook), I assume that query folding would never apply to those sources, is that right?

[Phoenixspin]

I knew one could fold towels but I didn't know one could fold queries. Cool.

[shamf]

does query folding happen on sharepoint online list?

[johanmusik]

What a great start on this year! Thx for the tips

[etherlords]

My source is mostly Oracle do here's what I do to improve the performance; write the query properly so that I can retrieve the data fast, set the timeout, only shaping and minor cleansing are done inside PBI... Nothing too much...

[hermesjrd]

Hi Ruth!, awesome Tips, Thanks a Lot and Happy New Year. Wishing You a great Year ahead!!

[っっ-qi]

This is what would happen when running an SQL query. For example you can grab a date range on the SQL side rather than pulling into power query and filtering.

[rayng]

What about creating a stored procedure or a view and calling it from PBI. I've not tested this, bit it may resolve the issue of doing multiple updates to your logic causing query folding to break. Great content!

[juansepowerplatform]

Hello, good to know that if you start with a SQL statement then query folding does not occur after that! Thank you

[giri]

Increamental refresh doesn’t work .. on SAP Hana database..

[dancastillo]

what software do you use to make your videos?

[TheVamos]

Thanks for this. I knew that m tries to push changes back up to the source, but didn't realise you could see the native query or its limitations. I tend to start with a handwritten sql so its a shame it's not going to help me. However this is useful to know.