About ten years ago, I applied for a SWE role at Facebook. During the interview, the only question that I didn't feel confident was when they asked me how group

About ten years ago, I applied for a SWE role at Facebook. During the interview, the only question that I didn't feel confident was when they asked me how group-by works in SQL and to write a group by query. I said I didn't know and usually looked it up, but they didn't want me to look it up. They rejected me, and the recruiter literally told me it was due to a lack of familiarity with SQL (something I'd been using with PHP for 6+ years at that point). Edit: I interviewed a year later, wasn't asked about SQL at all, absolutely fumbled my way through some networking questions, and was still hired, so it's clearly very dependent on who's interviewing you and what they ask.