code: private void buildJoinTreeForColumn(String aColName, boolean useOuterJoin, UserAlias aUserAlias, Map pathClasses)
  	{
  		String pathName = SqlHelper.cleanPath(aColName);
  		int sepPos = pathName.lastIndexOf(".");
  
  		if (sepPos >= 0)
  		{
  			getTableAlias(pathName.substring(0, sepPos), useOuterJoin, aUserAlias,
  						  new String[]{pathName.substring(sepPos + 1)}, pathClasses);
  		}
  	}
docs: build the Join-Information for name
  functions and the last segment are removed
  ie: avg(accounts.amount) -> accounts