Step 11 of 18 of the SQL tutorial. Melting points hang off listings, and listings hang off compounds, so the name and the temperature are two foreign key hops apart. Read the FROM clause as a path: start at melting_points, step up to the entry that claims it, step up again to the compound. Reverse the order of the joins and the result is identical — the engine's query planner decides how to walk it, not you. The shortest path in the schema is a single hop: structures holds each compound’s molecular weight, one row apiece, behind structures.compound_id.
It opens on the query SELECT c.preferred_name, c.formula, e.supplier, m.low_c, m.high_c FROM melting_points m JOIN catalog_entries e ON e.id = m.catalog_entry_id JOIN compounds c ON c.id = e.compound_id WHERE m.low_c >= 200 ORDER BY m.low_c DESC LIMIT 20, which you can run and change in place.
Ask the same question of a chemical dataset in SQL and in Mango and compare the two answers. The database is a SQLite file your browser downloads once and queries locally, so nothing you write ever leaves your machine — which is also why the tool needs JavaScript.