While Cypher borrows a lot of (good) ideas from SQL, the two languages are fundamentally different in their underlying model. SQL deals with Relational Algebra,

While Cypher borrows a lot of (good) ideas from SQL, the two languages are fundamentally different in their underlying model. SQL deals with Relational Algebra, while Cypher deals with Graph Theory. For that pattern to work in SQL, your SQL engine would need to be able to view its relations (tables) as a graph. I'm not smart enough to sort this out in my head, but my instinct tells me that it's better to have the two models separate, mixing them in one query seems like a recipe for confusion.