If you don't know how to do a JOIN you really don't know how to use SQL, and that's not a tricky use of JOINs at all. If you're hiring for a position that mostl

If you don't know how to do a JOIN you really don't know how to use SQL, and that's not a tricky use of JOINs at all. If you're hiring for a position that mostly uses an ORM or something and raw SQL is only important in cases where the ORM is giving bad performance, maybe not knowing how to do a three-table join is fine. If actually writing SQL is part of the job regularly, though, the sort of thing grandparent is talking about is absolutely a bare-minimum of knowledge needed, maybe even below the bare minimum.