How to write one datomic query, taking into account the whole set

Question

Is it possible to write such queries in datomic?

• find the name of the oldest child
• find the person with the lowest body mass index (weight / height)

Answer 1

[:find (max ?tuple) :where [?k :kid/age ?age] [?k :kid/name ?name] [(vector ?age ?name) ?tuple] 

Note:

• the order of the attributes in the expression (vector ?age ?name) matters

• the query returns one result, while we can expect a collection, because there can be many children in the age who are maximum in the set. You can use (max n ?tuple) to achieve this.

See also the Returning Aggregates section at http://docs.datomic.com/query.html

If you have something more specific, provide more details in the question and include your circuit.