Filtering for "new" or "unique" records but NOT by date

I do SEO analysis using Metabase (I highly recommend it) but I've come up with a scenario that I'm not sure how to solve.

All of my data is in one table, and yes, the keywords I track are duplicated many, many times but I have a date column that differentiates each duplicate of that keyword and a position column for where that word appears.

So I filter this week or position or contains or what have you.

But I'd like to know what is "new".

What keyword has not appeared before in my data. Which one is brand new right now.

I guess that leads to a knew question: I'd like to see keywords that have disappeared from the data?

Any ideas? I tried searching the forum burt I really couldn't find anything.

Hi @rgarcia
You would have to make such query in SQL, since that would be something that is more complex than what Metabase can do in the GUI.

Thank you for the response!
Darn, doing analysis through metabase has spoiled me rotten. I dread having to write up a sql query.