     }
 }
 
-/// :nodoc:
+/// Returns an aggregate that substracts an aggregate with the `*` SQL operator.
+///
+/// For example:
+///
+///     let request = Author.annotated(with: 2 * Author.books.count)
 public func * <RowDecoder>(lhs: SQLExpressible, rhs: AssociationAggregate<RowDecoder>) -> AssociationAggregate<RowDecoder> {
     return AssociationAggregate { request in
         let (request, expression) = rhs.prepare(request)

    }
}

/// :nodoc:
public func || <RowDecoder>(lhs: AssociationAggregate<RowDecoder>, rhs: AssociationAggregate<RowDecoder>) -> AssociationAggregate<RowDecoder> {
    return AssociationAggregate { request in
        let (lRequest, lExpression) = lhs.prepare(request)

    }
}

/// Returns an aggregate that compares an aggregate with the `<` SQL operator.
///
/// For example:
///
///     let request = Author.having(Author.books.count < 3)
public func < <RowDecoder>(lhs: AssociationAggregate<RowDecoder>, rhs: SQLExpressible) -> AssociationAggregate<RowDecoder> {
    return AssociationAggregate { request in
        let (request, expression) = lhs.prepare(request)
