count.js

var Promise = require('bluebird'),
    User    = require('./user'),
    knex, query;

knex = User.prototype._builder(User.prototype.tableName);
    
query = function (q) {
    q.distinct()
        .innerJoin('orders', function () {
            this.on('users.id', '=', 'orders.user_id')
                .andOn('orders.amount', '>', 100);
        })
        .innerJoin('addresses', function () {
            this.on('users.id', '=', 'addresses.user_id')
                .andOn('addresses.state', '=', 'New York');
        });
    return q;
};

Promise.all([
    query(knex.count()).first().then(function (row) {
        return +row.count;
    }),
    User.query(query).fetchAll({ withRelated: ['orders', 'addresses'] })
]).spread(function (count, users) {
    // success
});

count_and_fetch.js

var Promise = require('bluebird');

Model.countAndFetch = function (query, options) {
    return Promise.all([
        query(knex.count()).first().then(function (row) {
            return +row.count;
        }),
        this.query(query).fetchAll(options)
    ]);
};

query.js

User.query(function (q) {
        q.distinct()
            .innerJoin('orders', function () {
                this.on('users.id', '=', 'orders.user_id')
                    .andOn('orders.amount', '>', 100);
            })
            .innerJoin('addresses', function () {
                this.on('users.id', '=', 'addresses.user_id')
                    .andOn('addresses.state', '=', 'New York');
            });
    })
    .fetchAll({ withRelated: ['orders', 'addresses'] })
    .then(function (users) {
        var user      = users.at(0),
            orders    = user.related('orders'),
            addresses = user.related('addresses');
        // do stuff with the user, their orders, and their addresses
    });