parse.com selecting from join table - join

Question

Just wondering am I doing this correctly or is there a better way.
I have 3 tables, Game, User and UserGame. The UserGame is a join table has pointers to both Game and User tables.
The following script returns all the games that the user has joined.
var Game = Parse.Object.extend("Game");
var UserGame = Parse.Object.extend("UserGame");
var innerQuery = new Parse.Query(Game);
var query = new Parse.Query(UserGame);
query.equalTo("user", user);
query.matchesQuery("game", innerQuery);
query.include("game");
query.find({
I am now trying to return the games that the user has not joined. I tried the reverse of the above query but it does not work. Any ideas?
Also is there a better solution than using the join table above, should I just add a list of game pointers to the user table?

Answer 1

This is userful (and not easily accessible from the website)
https://parse.com/docs/js/symbols/Parse.Query.html
What you're trying to do seems like a good usecase of .noContainerIn([results of the first query]) or .doesNotMatchKeyInQuery
matchesKeyInQuery in your first example seems simpler to use BTW

Answer 2

I have used a table that has two pointers inside it too.I'm going to explain what I did simplified, and adpating it to your case:
1.Build a query with your object Game,to get an array of all games that exists in this table:
var Game = Parse.Object.extend("Game");
var query = new Parse.Query(Game);
query.find({
success: function(arrayGames) {
//store this array to manage later
},
error: function(user, error) {
alert("There is not stored games");
}
});
2. Get the user you want to compare to this games stored that points in the table UserGame, and make a Query for each element of the previous got array:
var UserGame = Parse.Object.extend("UserGame");
var query = new Parse.Query(UserGame);
var currentUser = Parse.User.current();
var currentGame;
for(var i=0; i<arrayGames.length ;i++){
currentGame=arrayGames[i];
query.equalTo("Game", currentGame);
query.notEqualTo("User", currentUser);
query.find({
success: function(foundGames) {
//you have got an array with the games not joined to this user
},
error: function(user, error) {
alert("There are not joined games ");
}
});
}
Hope it helps, ask me if you need more details ;)