"I use [x] all the time and know it well, so [x] will be a good filter for evaluating someone's technical skills."
No. People do different work tasks depending on the project or company.
Sometimes I'm knee-deep in SQL. Others in React. I'm often forced to do PHP. My familiarity with specific SQL syntax ebbs & flows with what I'm doing.
There's no point in keeping something in your brain if you're not going to use it every day. Just remember the general concept and Google the specifics when you need it.
Just one example why interviewing is terrible and interviewers really should be trained on what not to do.
Need me to write an ETL. I probably can't crank it out in an hour like a data scientists, but I can get it done in a reasonable amount of time. I just need to do some major context shifting.
Have me write only ETL's for a week, I'll be cranking them out after the first few.
Simply remembering that fact is language trivia that is easy to refresh when needed.
It’s like asking if intel x86 is big-endian or little-endian. It’s trivial to check but if I haven’t had to use that fact in a while, I likely won’t bother to remember because it’s trivial to search for.
I just don't use it enough to keep it in memory as a first class concept. A quick google search with an example is enough to jog my memory.
If I got asked about it on an interview, I'd be completely blank.