Return every flash point recorded below 0 °C, with the compound it was measured on, coldest first. A flash point hangs off a listing, not off a compound, so two joins stand between flash_points and compounds. Twelve rows answer this. Ethanethiol flashes at −45 °C, the lowest in the database.
A intermediate exercise, answered in SQL. It is marked by the rows your query returns rather than by how you wrote it, with 3 hints if you want them.
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.