Android GreenDao deep query n:m relationship

In my app the relationship is designed like this: and I want to select at least one user as a friend for all chats.

Basically, I want to execute the following query:\

SELECT c.* FROM CHAT c, USER u, UserChats uc 
  WHERE c.type = myType 
  AND u.isFriend = 1 
  AND c.id = uc.chatId 
  AND u.id = uc.userId

I haven't managed to find a way to do this in the GreenDao library, hopefully someone can help me with this.

EDIT:
This is what I have so far:

List<UsersChats> list = usersChatsDao.queryDeep(
    "WHERE T0." + UserDao.Properties.isFriend.collumnName + " = ? "+
    "AND T1." + ChatDao.Properties.type.collumName + " = ?",
    new String[] {"1", myType});

if(list != null && list.isEmpty() == false) {
    List<Chat> chats = new ArrayList<Chat>();
    for(UsersChats link : list) {
        chats.add(link.getChat());
    }
}

Solution 1:

Since grrendao doesn't do the  QueryBuilder.join() current method, I think your solution is the best one you can find right now, it uses joins internally.

There are only minor drawbacks to it:

• You may query more tables than you actually need
• You're iterating over a potentially huge list
• you cannot uselistLazy()

Another way is to use some query like this (assume  IsFriend yes  int-column and  myType fit to  ChatDao.Properties.type :

Query<Chat> qc = chatDao.queryRawCreate(
      " LEFT JOIN "+UserChatsDao.TABLENAME+" UC"+
      " ON T."+ChatDao.Properties.id.columnName+"=UC."+UserChats.Properties.chatId.columnName+
      " LEFT JOIN "+UserDao.TABLENAME+" U"+
      " ON UC."+UserChats.Properties.userId.columnName+"=U."UserDao.Properties.id.columnName+
      " WHERE U."UserDao.Properties.isFriend.columnName+"=?"+
      " AND T."+ChatDao.Properties.type.columnName+"=?", 1, myType);

Or (presumably less performance, etc.):

Query<Chat> qc = chatDao.queryRawCreate(
      " , "+UserChatsDao.TABLENAME+" UC"+
      " , "+UserDao.TABLENAME+" U"+
      " WHERE T."+ChatDao.Properties.type.columnName+"=?"+
      " AND U."+UserDao.Properties.isFriend.columnName+"=?"+
      " AND T."+ChatDao.Properties.id.columnName+"=UC."+UserChats.Properties.chatId.columnName+
      " AND U."UserDao.Properties.id.columnName+"=UC."+UserChats.Properties.userId.columnName, myType, 1);

Then you can use the desired  list() -method:

qc.list();
qc.listLazy ();
...