Lino contributed to the apache/calcite repository by enhancing SQL query optimization and correctness. He developed a feature that collapses nested expanded IS NOT DISTINCT FROM expressions within join conditions, using a RexShuttle-based recursive transformer in Java to simplify complex logical structures involving OR, CASE, AND, NULLIF, and NOT. Additionally, he fixed a bug in the detection of deeply nested window aggregations during SQL unparsing by implementing recursive traversal of SQL structures and adding targeted tests. Lino’s work demonstrated depth in compiler design, code refactoring, and SQL, resulting in more efficient query planning and improved code maintainability.