Knowing how to use raw SQL has been a major differentiator for me in tech interviews (I've been told by employers). It seems people jump to learning web frameworks and they either skip this part or worse, are told they don't need to know how to use it to be become decent and land a job.

I call bullshit, do not listen to such advice, grab a SQL book, install a SQL database management server (postgres for example) and start playing with it. Create tables, do left joins, learn about indexes, try playing with pivots, and some more advanced stuff like, try building a "data warehouse" type of structure. I can guarantee you, from personal experience, it is worth it. Bonus points if you do all that from the terminal, using psql for example. It makes you feel more confident when debugging a real issue and really impresses in interviews.