Bug 176963 Subquery's resultSetExpressions is not consistent between generate and present time.
In generate time, subquery will add the parent query's column binding to its own resultSetExpressions. While in present time, it only has the ones of itself.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/PreparedQuery.java
if( trans instanceof IGroupDefinition )
		{
			IGroupDefinition gd = (IGroupDefinition)trans;
			key = gd.getKeyColumn( ) != null ? gd.getKeyColumn( ):gd.getKeyExpression( );
		}
		this.exprManager.addBindingExpr( key, resultSetExpressions, groupLevel );
		
		
		Collection subQueries = trans.getSubqueries( );
		Iterator subIt = subQueries.iterator( );
		while ( subIt.hasNext( ) )
		{
			ISubqueryDefinition subquery = (ISubqueryDefinition) subIt.next( );
			PreparedSubquery pq = new PreparedSubquery( this.session, this.dataEngineContext,
					subquery,
					queryService,
					groupLevel );
			subQueryMap.put( subquery.getName(), pq);
			
			subQueryDefnMap.put( subquery.getName( ), new Object[]{
					subquery, new Integer( groupLevel )
			} );
		}
	}
	
	/**
	 * Prepares all expressions in the given collection
	 * 
	 * @param expressions
	 * @param groupLevel