Bug 124251 the data cann't been exported.
Description: the data cann't been exported. Steps to reproduce: 1. new a report 2. new a datasource and a data set(DS_A) 3. use an external library 4. drag a table to the report layout from the imported library 5. insert an another table into the layout of the report and bind the data set(DS_A) 6. preview in the 'Web Viewer' and export the data Actual result: The data can been exported. Expect result: The data can been exporteded
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/DataExtractionTask.java
public IExtractionResults extract( ) throws EngineException
	{
		if ( currentResult != null )
			return currentResult;
		
		if( instanceId != null )
		{
			return extractByInstanceId( );
		}
		else if( resultSetName != null )
		{
			return extractByResultSetName( );
		}
		return null;
	}
	
	/*
	 * export result directly from result set name
	 */
	private IExtractionResults extractByResultSetName( ) throws EngineException
	{
		assert resultSetName != null;
		assert executionContext.getDataEngine() != null;
		
		prepareMetaData( );
		
		DataEngine dataEngine = executionContext.getDataEngine().getDataEngine();
		try
		{
			IBaseQueryDefinition query = (IBaseQueryDefinition)mapResultSetNameToQuery