the only real differences between a query language and a normal language are quantification and unification. quantification is something that seems pretty easy to paper over (i.e by just having functions that operate on Set types).
SPJ is/was working on a lanauge Verse which provides a procedural looking language that is actually either fully unification or region-based under the hood. trivially this is just allowing relations (tables or functions) to implement only a subset of input/output signatures
so yes, I think its a great idea to just smoosh the two together, particularly if its in a host language with sufficient meta programming facilities to extract out the relational parts and evaluate them as streams
