SQL is not a bad language. However, it's far from flexible and reusable. The biggest issue I always have with SQL is the fact that I can hardly reuse any piece of my code.

Let me give you an example.

select vendor, model, avg(price) as price from allCars group by vendor, model;

So far, this is simple and clear. Now let's imagine someone has a requirement to calculate this for different set of cars:

select vendor, model, avg(price) as price from allCars where vendor = 'BMW' group by vendor, model;

or

select vendor, model, avg(price) as price from allCars where year > 1990 group by vendor, model;

This approach only works if I'm always selecting from the same table - allCars, and I know all the condition in advance. To reuse the actual code which calculates the average prices (select ... group by) I'd need something like this:

select vendor, model, avg(price) as price from $cars -- $cars is a variable with at least three attributes (vendor, model, price) group by vendor, model;

This way I could write my own relational operator which calculates avg prices of cars per vendor and a model no matter where the cars are coming from.

Does anyone else have the same problem as me or am I just not smart enough to figure out how to do it in SQL?