Comment by barrkel

It's a fair sentiment, but it can be handled without losing directional flow and composability, some of the bigger advantages of reworking SQL.

One idea would be along the lines of a function prototype: a declaration, up front, about the columns and types that a query is expected to return. It's a good place to put documentation, it's redundant information which should protect against mistakes but not so redundant that it would be too taxing - the author should know what the query returns. The prototype would only be used for validation of column names and types.

Another idea would be requiring the last element in a query to be a projection, a bit like the return statement in a function body: here's what I'm returning out of the grand set of symbols available (e.g. via various joins) in scope from previous operations in the flow.