My company is in the process of hiring an email production manager, but we haven't figured out a great way to check that candidates are self-sufficient with regard to HTML and SQL.

We are a fairly technical and data-driven company, and we need our new email manager to be able to update HTML templates and create new ones without being reliant on a developer. We also need this new email manager to be able to write SQL queries and understand our database structure.

What best practices or questions do you use in your interviews to check for technical ability? Do you ask open-ended questions; ask candidates to provide examples of previous work; or give the candidates HTML or SQL tests?

All suggestions and feedback are helpful. Thank you in advance!