Node.js mysql query passing to next function in async.waterfall

I have some code in node.js using express. I route a call to request data from a mysql database, and what I want to do is pass that to another function to restructure the returned json from a tabular form (table query) to a hierarchy type json.

I've tested the script separately to restructure the output from my sql query. However, I am having trouble passing it from my query function to my new script(function)

I'm just not seeing what I am doing wrong. Any help please and thanks.

exports.get_site_menu = function (req, res) {
    var dbc;
    console.log('In menu setup');
    async.waterfall([
        // get a connection

        function (callback) {
            db.db(callback);
        }

        ,
        querylookup, modifyjson
    ], completed);

    function querylookup(dbclient, res) {
        dbc = dbclient;
        dbc.query("SELECT categories, " +
            "subcategories, " +
            "pid, " +
            "title, " +
            "description " +
            "FROM MENU_SELECT_ACTIVE_VIEW " +
            "where company_id = ? and site_id = ?", [req.query.companyid, req.query.siteid], res);
    }

    function modifyjson(err, res) {

        categories = [];

        console.log('results ' + res);

        res.forEach(function (entry) {
            var cindex = categories.map(function (category) {
                return category.name;
            }).indexOf(entry.categories);

            console.log(cindex);
            if (cindex < 0) {
                // Not found in categories array
                cindex = categories.push({
                    name: entry.categories,
                    subcategories: []
                }) - 1; // -1 to fix the index
            }
            // Lets search the subcategory
            var category = categories[cindex];

            var sindex = category.subcategories.map(
                function (subcategory) {
                    return subcategory.name;
                }
            ).indexOf(entry.subcategories);

            if (sindex < 0) {
                // Not Found
                sindex = category.subcategories.push({
                    name: entry.subcategories,
                    items: []
                }) - 1;
            }
            // Subcategory exists. Just push
            category.subcategories[sindex].items.push({
                pid: entry.pid,
                description: entry.description,
                title: entry.title
            });
        });

        menu = {
            menu: {
                categories: categories
            }
        };
        console.log('menu ' + menu);
    }


    function completed(err, menu, fields) {
        if (dbc) dbc.end();
        if (err) {
            callback(err);
        } else {
            console.log(menu);
            res.contentType('json');
            res.send(JSON.stringify(menu));
        }
    }
};