Coming also from a SE/Practical background, the only time I need to use those complex expression in a SQL query, is when someone screwed up the datamodel, or ov

Coming also from a SE/Practical background, the only time I need to use those complex expression in a SQL query, is when someone screwed up the datamodel, or over-engineered it. In theory you can do many things with SQL, but none of those things perform better than a straight up select query, which is usually what you're after-- performance.