Gmail: how to filter messages from a specific sender into inbox if they have either of two keywords, and delete all messages with neither keyword

Question

I'm working for a nonprofit that serves people charged with federal crimes. We track their cases online using a system that sends an email to us every time something happens in their case. That's a huge amount of email though, and up to this point we've only really cared about sentencing hearings.

So, I currently have our Gmail account set up with the following filters:

Matches: from:(case-updates@app.com) sentencing
Do this: Apply label "Sentencing Update", Never send it to Spam, Categorize as Primary

Matches: from:(case-updates@app.com) -sentencing
Do this: Delete it

We've decided we also want to get emails that contain the phrase "Trial held." I'm pretty comfortable creating the filter that would get something with that phrase into my inbox and labeled, but I'm less clear on how to update the deletion filter. It seems to me there are two options for NOT/- filters with multiple queries:

1. delete everything that contains both queries
2. delete everything that contains either query
3. delete everything that contains neither query

I want option number three. What should the filter look like? I could see 1 or 3 being what happens when you use an AND operator and 2 and 3 happening when using an OR operator...

Answer 1

To DELETE ALL emails from case-updates@app.com EXCEPT ones that contain "sentencing" AND/OR "Trial Held":

from:(case-updates@app.com) -{"sentencing" "Trial Held"}

Notes:

1. Putting curly braces "{}" around terms implies OR for it's contents.
2. If you don't put quotes around a singular word google can return pluralizations. e.g. sentencing = sentencings You can also use the plus "+" sign in lieu of quotes:

from:(case-updates@app.com) -{+sentencing "Trial Held"}

3. You need quotes around "Trial Held" if you are only looking for instances where they show up side by side.

4. If your system is putting tags in the subject line then you can restrict the search to subjects to avoid unforeseen errors:

from:(case-updates@app.com) -{subject:("sentencing") subject:("Trial Held")}

Warning: I would be inclined to archive and label the offending emails (instead of immediately deleting them) since (1) they can be deleted en-masse at any point. (2) the storage is not a concern, (3) they don't need to be seen or sync'ed and (4) perhaps more importantly, while "you" may not be prone to errors or oversights, keep in mind you are getting advice from "me", who is, so I encourage you to be careful when deleting even if you really really know what you are doing. :-)