Return every boiling point recorded below atmospheric pressure for a compound that also has one at 760 mmHg, with the compound, the pressure and the temperature. The reduced-pressure rows only mean something next to the atmospheric one, so the atmospheric row is a condition on the compound, not a row to return. Order by name, then pressure, then temperature. Forty-nine rows answer this: 1,2-Diaminocyclohexane boils at 188 °C at 760 mmHg, 104 °C at 40 mmHg and 79 °C at 15 mmHg.
A advanced 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.