Saurabh Dubey Really useful post! I liked the point that SQL should be learned step by step, not by memorizing random queries. Once the basics are clear, moving toward joins, aggregations, CTEs, and ...
Custom structs need # [derive (Hash, Eq, PartialEq)]. Spent 15 minutes on "the trait `Hash` is not implemented" before I figured it out. Performance note: Vec is fast because it's contiguous memory.