Bug 122854 There is redundant columns in "available columns" list in "export data" dialog.
Description: There is redundant columns in "available columns" list in "export data" dialog. Steps to reproduce: 1. Preview attached design in web viewer. 2. Select the table and click on "export" button. 3. There is a "detail" column name in "available columns" list which is not data set column.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/data/dte/ReportQueryBuilder.java
* @return the filter
		 */
		private IFilterDefinition createFilter( FilterConditionHandle handle )
		{
			String filterExpr = handle.getExpr( );
			if ( filterExpr == null || filterExpr.length( ) == 0 )
				return null; 
			
			String filterOpr = handle.getOperator( );
			if ( filterOpr == null || filterOpr.length( ) == 0 )
				return new FilterDefinition( new ScriptExpression( filterExpr ) );
			/*
			 * has operator defined, try to convert filter condition to
			 * operator/operand style column filter with 0 to 2 operands
			 */
			String column = filterExpr;
			int dteOpr = ModelDteApiAdapter.toDteFilterOperator( filterOpr );
			String operand1 = handle.getValue1( );
			String operand2 = handle.getValue2( );
			return new FilterDefinition( new ConditionalExpression( column,
					dteOpr, operand1, operand2 ) );
		}
		/**
		 * create a filter array given a filter condition handle iterator
		 * 
		 * @param iter
		 *            the iterator
		 * @return filter array
		 */
		private ArrayList createFilters( Iterator iter )