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
PreparedSubquery subquery = (PreparedSubquery) subQueryMap.get( subQueryName );
		if ( subquery == null )
		{
			DataException e = new DataException( ResourceConstants.SUBQUERY_NOT_FOUND,
					subQueryName );
			logger.logp( Level.FINE,
					PreparedQuery.class.getName( ),
					"execSubquery",
					"Subquery name not found",
					e );
			throw e;
		}
		return subquery.execute( iterator, subScope );
	}
	
	/**
	 * Closes the prepared query. This instance can no longer be executed after
	 * it is closed 
	 * 
	 * TODO: expose this method in the IPreparedQuery interface
	 */
	void close( )
	{
		this.baseQueryDefn = null;
		this.aggrTable = null;
		this.subQueryMap = null;
		
		logger.logp( Level.FINER,
				PreparedQuery.class.getName( ),
				"close",