Bug 132805 Set descending to outer group will affect inner group.
Description: Set descending to outer group will affect inner group. Steps to reproduce: 1. New a sample datasource and dataset from orders. 2. Drag the dataset to Layout. 3. Add a group on ordernumber, interval 10, descending. 4. Add another group on orderdate, interval day 2, ascending. 5. Preview. Expected result: Data are grouped correctly. Actual result: Inner group didn't work unless you set outer group's sort to asc.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/QueryExecutor.java
openDataSource( );
		
		
		dataSet.beforeOpen();
					
		IExpressionProcessor exprProcessor = new ExpressionProcessor( null,
				null,
				dataSet,
				null );
		
		
		odiQuery = createOdiQuery( );
		odiQuery.setExprProcessor( exprProcessor );
		populateOdiQuery( );
		prepareOdiQuery( );
		isPrepared = true;
	}
	
	/**
	 * Open the required DataSource. This method should be called after
	 * "dataSource" is initialized by findDataSource() method.
	 * 
	 * @throws DataException
	 */
	protected void openDataSource( ) throws DataException
	{
		assert odiDataSource == null;