SQL is already a pretty functional language. It's a nice low statefulness, transactional layer around a very stateful core of data. Fully exploiting this gives

SQL is already a pretty functional language. It's a nice low statefulness, transactional layer around a very stateful core of data. Fully exploiting this gives you many benefits. This is the reason noSQL databases tend to be subpar. Also, huge are the performance benefits of not always pulling data across multiple layers of cache, across the network, back into multiple layers of cash of another computer to be processed by some script running far away from the original data. Processing and aggregating as much as you can as you are retrieving the data is often multiple orders of magnitude faster and more efficient than sending everything elsewhere to be processed.