[Koha] Need a little help with an SQL query

[Chris Brown]

Gentle Reader,

We want to get a list of all patrons for who we do *not *have email
addresses but who are "active" (for example, have checked a book out in the
last 6 months)

I know how to get a list of patrons with no email address but my knowledge
of SQL and the database schema aren't good enough to write the "AND have
checked a book out in the last 6 months" part of the query.

Is there a kind soul out there who could help? We are using Koha 17.11

Thanks and Best Regards,

Chris Brown