How to join two rollup column to a single array and filter out duplicate values?

I’m using my airtable to attached keywords images.

I have one big keywords table with multiple categories of different keywords. Then i have multiple linked columns to the different categories. However some of the keywords overlap into different categories.

So I thought I could rollup all my linked columns and do something like this:

ARRAYUNIQUE(ARRAYJOIN(ARRAYJOIN({RollUp1}) & IF({RollUp2}, ‘,’ & ARRAYJOIN({RollUp2})) & IF({RollUp3}, ‘,’ & ARRAYJOIN({RollUp3}))))

However I still have duplicates of keywords in my final array.

After that I tried to make every possible combination of


But still the same.

I’ve also tried to change my rollups to lookups, but no luck either.

I have the feeling that it’s something to do with how I try to join the three columns that might be the issue.

Does anyone know how I can join my rollups and then filter out all the duplicates?

There is no practical way to do this with formula fields. When you use ARRAYJOIN() or the & operator, the end result is a text string, and not an array. Thus ARRAYUNIQUE() no longer sees the individual items that were in the original array; it only sees the single text string. ARRAYUNIQUE() also only acts upon the first parameter, so including different arrays as different parameters doesn’t work either.

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Thank you for confirming this @Kuovonne