[Ataraxy]

So, I've been trying to figure this out a bit lately.

How would you go about writing a customer facing query builder that is analogous to the MongoDB aggregation pipeline with SQL?

With MongoDB I could conceivably generate/store a JSON object for such a query. In SQL it seems a lot more obtuse to do.

[jahewson]

Keep it simple: stick with MongoDB-like JSON objects for queries but write some code to map those queries to SQL immediately before execution.