using Filter in Gallery

[WaMCHCH]

Hello, I'm trying to use lookup and filter but not sure how to go about this, 

Currently I have two CDS: 

    1-   L5QuestionList {L5QuestionNumber,Heading}

    2-   QuestionHeading {HeadingID, HeadingDescription}

In PowerApps, currently I have a Gallery that display items = QuestionHeadings

Question: How do I filter the gallery to only display a certain heading? 
**I want it to lookup from Source L5QuestionList and only display HeadingDescription from source QuestionHeading if L5QuestionList.Heading = QuestionHeading.heading  (so that if there is no question under a heading it won't be display)

[mdevaney · Accepted solution]

@WaMCHCH 

Here's a nice one-liner solution to your question.  Put this code in the Items property of your gallery for QuestionHeading.

Filter(QuestionHeading,HeadingID in L5QuestionList[@Heading])

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[WaMCHCH]

Hi, @mdevaney  thank you for your reply, I have tried your code but i got error:

Filter(QuestionHeading,HeadingID in L5QuestionList[@Heading])

it doesn't recognize L5QuestionList  data source, so I got an error saying: "The specified  column is not accessible in this context"

[mdevaney]

@WaMCHCH

I tested the solution using by making a collection where Heading was a string type column and it worked.  The reason it does not work you must be that Heading is a different column type such as a complex column.  I'm not sure what to do next here...

[WaMCHCH]

@mdevaney thank you

in the two CDS i have QuestionHeading with HeadingID as primary key

and in QuestionList I have a Heading which is a lookup from QuestionHeading  
I'm not very familiar with collection, I will try and look at some example and try to approach filtering with collection instead...