Bug 142939 Invalid interval will cause incorrect group action.
Description: Invalid interval will cause incorrect group action. Steps to reproduce: 1. Insert a list 2. Add a group, key is string type column, set interval to year, range to 3 3. Preview Expected result: Error msg about invald interval and ignore the invalid interval. Actual result: No error msg and only return one group with all datarows.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/QueryExecutor.java
* 
	 * @return
	 */
	abstract protected DataSourceRuntime findDataSource( ) throws DataException;
	/**
	 * Create a new instance of data set runtime
	 * 
	 * @return
	 */
	abstract protected DataSetRuntime newDataSetRuntime( ) throws DataException;
	/**
	 * Create a new unopened odiDataSource given the data source runtime
	 * definition
	 * 
	 * @return
	 */
	abstract protected IDataSource createOdiDataSource( ) throws DataException;
	/**
	 * Create an empty instance of odi query
	 * 
	 * @return
	 */
	abstract protected IQuery createOdiQuery( ) throws DataException;
	/**
	 * Prepares the ODI query
	 */
	protected void prepareOdiQuery( ) throws DataException
	{
	}
	/**