Bug 168177 [2.1.2][regression]DataException when preview attached report in Web Viewer.[0901]
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/ServiceForQueryResults.java
result.putAll(populateSubQueryColumnBindings(defn.getSubqueries()
					.iterator()));
			return result;
		}
		/**
		 * 
		 * @param groups
		 * @return
		 */
		private Map populateGroupColumnBindings(Iterator groups) 
		{
			Map result = new HashMap();
		
			while (groups.hasNext()) 
			{
				IGroupDefinition gd = (IGroupDefinition) groups.next();
			
				result.putAll(populateSubQueryColumnBindings(gd.getSubqueries()
						.iterator()));
			}
			return result;
		}
		/**
		 * 
		 * @param subs
		 * @return
		 */
		private Map populateSubQueryColumnBindings(Iterator subs)