Bug 132515 Expression like "Toltal.rank(Tolta.ave(row[a]),ture,Null,1)" is return an error
Description: Add an expression like "Toltal.rank(Tolta.ave(row[a]),ture,Null,1)" is return an error.The nesting "Toltal" seem not to be work. Step to reproduce: 1.new a datasource and dataset 2.drag the dataset to layout veiw for a table 3.set a group on the table 4.Insert a data into the group header with the expression e.g. "Toltal.rank(Tolta.ave(row[a]),ture,Null,1)" Actual result: An error was thrown out Expected result: It should work correctly in order to support some requirments
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/QueryExecutor.java
return DataType.UNKNOWN_TYPE;
		}
		if ( columnName.equals( "__rownum" ) )
		{
			return DataType.INTEGER_TYPE;
		}
		Object baseExpr = ( this.baseQueryDefn.getResultSetExpressions( ).get( columnName ) );
		if ( baseExpr == null )
		{
			return DataType.UNKNOWN_TYPE;
		}
		return ( (IBaseExpression) baseExpr ).getDataType( );
	}
	
	/**
	 * @param src
	 * @return
	 */
	private String getGroupKeyExpression( IGroupDefinition src )
	{
		String expr = src.getKeyColumn( );
		if ( expr == null )
		{
			expr = src.getKeyExpression( );
		}
		else
		{
			expr = getColumnRefExpression( expr );
		}
		return expr;