Someone posted recently with a question about how to filter on multiple select fields with SuiteQL. Slack has, of course, swallowed that message. I had the same struggle as that poster, and the solution that I worked out for this was deeply unsatisfying. No longer! I found this SuiteAnswers article that documents how to get access to the mapping table between the main record and the custom list to join into your query to achieve this goal. Hope it helps someone else here, because it's really helping me 😄