SQL is amazing but the mental model beyond inner joins is not at all obvious. Things like outer joins (and when you need them), aggregation, partitioning etc..

SQL is amazing but the mental model beyond inner joins is not at all obvious. Things like outer joins (and when you need them), aggregation, partitioning etc... I am sure I've missed a few things. But SQL is absolutely amazing. You have to understand the data and the relations, what's not in the data that you'd expect to be etc...