Problem

IvorySQL implements Oracle-style ROWNUM, but the query and SELECT documentation does not explain assignment order, predicate behavior, common top-N mistakes, or current limitations.

Proposed change

Add a focused ROWNUM section with selection, pagination, DML, query-level scope, migration examples, and compatibility notes.

Acceptance criteria

• Evaluation semantics and common counterexamples are documented.
• Practical top-N and pagination patterns are included.
• Current set-operation and lateral limitations are stated.
• The complete SGML validation passes.