How can I filter one collection of SharePoint items to show items NOT in another collection of SharePoint items?

[pwrappr01]

I have two collections containing SharePoint list data. I want to show items in a gallery from Collection A that do NOT exist in Collection B, and I want to do this by comparing emails from a SharePoint Person column.
Here's the example:

Collection A:

Person

Table

Table

Collection B:

Date	Person
7/2/2020	Table
7/2/2020	Table

Since the "tables" are from SharePoint, this is a sample of what they contain:

DisplayName	Email
Joe Smith	jsmith@email.com

I figured I'd do something like this in the Gallery's Items property, but this obviously doesn't work:

Filter(CollectionB,Not(CollectionB.Person.Email in CollectionA.Person.Email))

[mdevaney]

@pwrappr01 
Your formula is very close to the solution.  Here's how I would write it 🙂

Filter(CollectionA, !(Person.Email in CollectionB.Person.Email))

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[pwrappr01]

@mdevaney, thanks for the response. I tried this, but the CollectionB.Person.Email throws an error ("Name isn't recognized") when used in conjunction with the in operator for some reason. It works everywhere else in the app when invoked.

[v-bofeng-msft · Accepted solution]

Hi @pwrappr01 :

Please check the following two situations:

Case1:If the person fileds in collectionA and collectionB are all table type,Please try this code:

Filter(CollectionB,!(First(Person).Email in Ungroup(CollectionA,"Person").Email))

Case2:If the person fileds in collectionA is  table type but the person fileds in collectionB is  record type ,Please try this code:

Filter(CollectionB,!(Person.Email in Ungroup(CollectionA,"Person").Email))

Best Regards,

Bof

[pwrappr01]

@v-bofeng-msft, Case #2 worked like a charm. Thank you much, and thank you, @mdevaney, for posting to assist.