Refactoring Add script to count unique learners in Sensei

[jonathanbossenger]

Update to #2172
Fixes #2111
Add sanitization for query strings
Use wpdb->prepare for SQL query

[jonathanbossenger]

@bsanevans In attempting to refactor #2172 to include sanitizing the query variables and to use $wpdb->prepare for the query, I had to make quite a few changes to the code.

Could I ask you to get @m1r0 to review this refactored version to confirm it would still work functionally the same as the original code, then I'll get someone else from the meta team to review it.

[kaitohm]

I've reached out to @m1r0 .

[m1r0]

Hello, hello! 👋 🙂

still work functionally the same as the original code

The only functional difference I'm noticing is that now both dates are needed. If that's intended, I've left some feedback.

Everything else looks solid. 🪨

[kaitohm]

It would be great if we didn't need to set both dates. For example, if we could get all data from a specific date until today without needing to set today's date, that would be great.

@jonathanbossenger Is that a change you can implement?

[jonathanbossenger]

Thanks @m1r0 and @bsanevans I've updated the PR.

@pkevan This PR is an update to #2172, adding sanitization to the date variables, and changing the SQL concatenation to use a prepared statement.

Could we ask you to give this a review?

Thanks

[pkevan]

👍 Looks good