Loop + queries + Q

gistfile1.js

var mysql = require('mysql');
var Q = require("q");

function createConnection() {
	var conn = mysql.createConnection({
	  host     : 'localhost',
	  user     : 'root',
	  password : 'password',
		database : 't2'
	});
	conn.connect();
	return conn;
}

var deferred = Q.defer();
var promises = [];

var conn = createConnection();

conn.query("SELECT * FROM corpora WHERE `type` = 'dependency' AND `status` = 'beta'", 
	function(err, rows, fields) {
		if(err) {
			deferred.reject(new Error(err));
		} else {
			deferred.resolve(rows.map(function(row) {
				return row['id'];
			}));			
		}
	});

var d2_list = [];
var d3_list = [];

var d1 = deferred.promise.then(function(corpus_id_list) {
	corpus_id_list.forEach(function(corpus_id) {
		var d2 = Q.defer();
		conn.query("SELECT id FROM textunits WHERE corpus_id = ?", [corpus_id], 
			function(err, rows) {
				if(err) {
					d2.reject(new Error(err));
				} else {
					d2.resolve(rows.map(function(row) {
						return row['id'];
					}));
				}
			});
		d2_list.push(d2.promise.then(function(textunit_id_list) {
			textunit_id_list.forEach(function(textunit_id) {
				var d3 = Q.defer();
				conn.query("SELECT * FROM annots WHERE textunit_id = ? ORDER BY rev DESC", [textunit_id], 
					function(err, rows) {
						if(err) {
							d3.reject(new Error(err));
						} else {
							d3.resolve(rows[0]);
						}
					});
				d3_list.push(d3.promise.then(function(annot) {
					console.log(annot.id);
				}));
			});
		}));
	});
	
}).fin(function() {
	console.log("FIN 1", d2_list.length);
	Q.all(d2_list).fin(function() {
		console.log("FIN 2", d3_list.length);
		Q.all(d3_list).fin(function() {
			console.log("END");
			conn.end();
		});
	});	
});