Step 2 of 18 of the SQL tutorial. WHERE drops the rows that fail a test, and two tests joined by AND must both hold. Mango writes the same conjunction as two keys of one object — there is no $and to type. An operator is a nested object: {"$gte": 8} where SQL writes >= 8. Both come back with 26 compounds, each with at least eight degrees of unsaturation — two benzene rings’ worth.
It opens on the query SELECT preferred_name, formula, unsaturation, nb_suppliers FROM compounds WHERE unsaturation >= 8 AND nb_suppliers >= 20 ORDER BY nb_suppliers DESC, 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.