I'm not trying to move the goalposts -- you've mentioned SQL specifically, and not relational databases in general -- but RDBM systems offer these features, and in a way that's compatible with access via SQL. Foreign data wrappers can present external data sources as if they were SQL views, allowing cross-source relations to be constructed and queried. Complex row level access and business can be implemented in stored procedures and triggers, if a simpler method can't be found. People will debate the extent to which these features ought to be used, but they certainly exist.
My point is that it isn't "downright nonsensical" at all.
My point is that it isn't "downright nonsensical" at all.