Convert Ruby regex to Postgres regex, for selecting invalid email addresses

I've done some internet trawling, and some reading of the Postgres regex docs, but I'm at the stage where I think asking a question here is the best thing to do. I have the following Ruby regex:

/\A[^@\s]+@([^@\s]+\.)+[^@\W]+\z/

Which I am trying to convert into a Postgres regex. So far I have come up with:

'\\A[^@\\s]\+@([^@\\s]+\\.)\+[^@\\W]\+\\z'

As I found this in one article online: > Thus, + is a metacharacter in PostgreSQL, whereas \+ is a plain “plus” character. and this in another: > The backslash is used to escape characters in PostgreSQL strings. So a regular expression like \w that contains a backslash becomes \\w when written as a literal string in a PostgreSQL statement. To match a single literal backslash, you’ll need the regex \\ which becomes \\\\ in PostgreSQL. The total query I'm running is this:

SELECT email
FROM users
WHERE email !~ '\\A[^@\\s]\+@([^@\\s]+\\.)\+[^@\\W]\+\\z'

And I'm expecting it to return zero results, bit it looks like it is selecting **all** email addresses. I'm expecting no results because I've used the operator !~ (I've also tried !~*), which I think returns non-matches, and because I'm pretty sure that all the email addresses in my database do match the Ruby regex I pasted at the top of this question. (This in turn is because we use Devise in a Rails app to validate all user emails, with the default email validation settings) So I've come to the conclusion that I've not converted my regex format/syntax correctly for Postgres, but also that I don't know what else I'm missing. Please can you help me understand whether this is possible, and if so, what else I need to change. --- Once I have successfully translated that regex, I have a second Ruby regex which I also want to translate into Postgres, which is this one:

/\A[a-zA-Z0-9.!\#$%&'*+\/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*\z/

This is because I want to find all the user emails that don't have a valid email address according to the spec here: https://html.spec.whatwg.org/multipage/input.html#valid-e-mail-address Thanks so much in advance 🙏