Apologies if this is basic for probably most of you but I just can't get my head around it. I have a flat table in sql server which contains lots of duplicates, differing only by one column. Id,Name,Desc,Date,Etc 1,abc,abc abc,2022-11-17,a 2,abc,abc abc,2022-11-17,a 5,def,def def,2022-11-17,a 4,abc,abc abc,2022-11-17,a 3,def,def def,2022-11-17,a 6,xyz,def def,2022-11-17,a I'm trying to write a query that finds all duplicates *excluding the ones with the highest Id*. So for the above example it would return the following: Id,Name,Desc,Date,Etc 1,abc,abc abc,2022-11-17,a 2,abc,abc abc,2022-11-17,a 3,def,def def,2022-11-17,a There are many millions of rows to process so looking for something efficient. Any advice would be appreciated. Regards Tom