Your comment made me realize why I prefer to work in ORMs instead of raw SQL, even though I'm frequently frustrated by their limitations - it all comes down to composability.

The mongodb syntax looks like it supports composing statements much more readily than SQL. It makes me wonder if there's been any serious work done making a query language that's fully as general as SQL, but is designed to be safely and easily composable so that you can build queries up from parts.

Anyone know of such a thing? The mongodb approach of query-as-data-structure is as close as I've seen.