在REST API中组合2个查询的输出

Question

我正在使用node.js restify模块.我有一个REST API,它在json中输出单个MySQL查询的结果.这是API的代码;

var rest_api_get_list = function (app, url_name) {
    function respond(req, res, next) {
        var door_mac = req.query.door_mac;

        var connection = own_mysql.getMySQL_connection();

        var query_str =
                "SELECT doors.mac_addr, " +
                "sensors.sensor_type " +
                "FROM sensors " +
                "WHERE (doors.mac_addr = ?) "
            ;

        var query_var = [door_mac];

        var query = connection.query(query_str, query_var, function (err, rows, fields) {
            //if (err) throw err;
            if (err) {
                //throw err;
                console.log(err);
                logger.info(err);
            }
            else {
                res.send(rows);
            }
        }); 
        return next();
    }

    app.get(url_name, respond);
};

假设我有另一个看起来像这样的查询;

    var query_str_2 =
            "SELECT knobs.mac_addr, " +
            "furniture.furniture_type " +
            "FROM furnitures" +
            "WHERE (knobs.mac_addr = ?) "
        ;

我想了2个MySQL查询的输出相结合query_str,并query_str_2与有REST API返回的结果中JSON.如何才能做到这一点？

为了更清楚,我正在考虑代码做这样的事情;

var rest_api_get_list = function (app, url_name) {
    function respond(req, res, next) {
        var door_mac = req.query.door_mac;

        var connection = own_mysql.getMySQL_connection();

        var query_str =
                "SELECT doors.mac_addr, " +
                "sensors.sensor_type " +
                "FROM sensors " +
                "WHERE (doors.mac_addr = ?) "
            ;

        var query_var = [door_mac];

        var query = connection.query(query_str, query_var, function (err, rows_output_1, fields) {
            //if (err) throw err;
        }); 

        var query_str_2 =
            "SELECT knobs.mac_addr, " +
            "furniture.furniture_type " +
            "FROM furnitures" +
            "WHERE (knobs.mac_addr = ?) "
        ;

        var query_2 = connection.query(query_str_2, query_var, function (err, rows_output_2, fields) {
            //if (err) throw err;

        }); 

        //How to display json output of rows_output_1 and rows_output_2?

        return next();
    }

    app.get(url_name, respond);
};

编辑:我开始赏金以吸引使用Promises的答案.

Answer 1

用于管理异步控制流的模块(如异步)可以帮助您解决此问题.

例如:

function respond(req, res, next) {

    var door_mac = req.query.door_mac;
    var connection = own_mysql.getMySQL_connection();
    var query_var = [door_mac];

    async.parallel([
        function (callback) {

            var query_str =
                "SELECT doors.mac_addr, " +
                "sensors.sensor_type " +
                "FROM sensors " +
                "WHERE (doors.mac_addr = ?) "
            ;
            connection.query(query_str, query_var, callback); 
        },
        function (callback) {

            var query_str_2 =
                "SELECT knobs.mac_addr, " +
                "furniture.furniture_type " +
                "FROM furnitures" +
                "WHERE (knobs.mac_addr = ?) "
            ;
            connection.query(query_str_2, query_var, callback);
        }
    ], function (error, results) {

        // results[0] => result for query_str
        // results[1] => result for query_str_2
        // ... return next() or whatever
    })       
}