SELECT COALESCE(TO_CHAR(calendaryear), 'All years') AS Year,  
            COALESCE(channelname, 'All channels') AS Channel, 
            COUNT(DISTINCT orderkey) AS Orders_Num
FROM dimorderchannel doc INNER JOIN factonlinesales fos
                ON doc.channelkey = fos.channelkey
            INNER JOIN dimdate dd 
                ON dd.datekey = fos.orderdatekey
WHERE calendaryear IN (2023, 2024)
GROUP BY GROUPING SETS ( (TO_CHAR(calendaryear), channelname),
                                                (TO_CHAR(calendaryear)),
                                                (channelname),
                                                () 
                                                )
ORDER BY 1, 3 ;