Code Example 1:

create table marxBrothers (
   Number int,
   Name varchar(32)
)
go
insert marxBrothers
    select 1, 'Groucho Marx' UNION ALL
    select 2, 'Harpo Marx' UNION ALL
    select 3, 'Chico Marx' UNION ALL
    select 1, 'Groucho Marx' UNION ALL
    select 2, 'Harpo Marx' UNION ALL
    select 3, 'Chico Marx' UNION ALL
    select 6, 'Zeppo Marx' UNION ALL
    select 7, 'Gummo Marx' UNION ALL
    select 6, 'Zeppo Marx'

begin tran deduplicate
    select DISTINCT *
    into #temp
    from marxBrothers

truncate table marxBrothers

insert marxBrothers
    select *
    from #temp

select * from marxBrothers

drop table #temp
commit tran deduplicate

drop table marxBrothers

Code Example 2:

create table marxBrothers (
    ident int IDENTITY,
    Name varchar(32)
)
go
insert marxBrothers (Name)
    select 'Groucho Marx' UNION ALL
    select 'Harpo Marx' UNION ALL
    select 'Chico Marx' UNION ALL
    select 'Groucho Marx' UNION ALL
    select 'Harpo Marx' UNION ALL
    select 'Chico Marx' UNION ALL
    select 'Zeppo Marx' UNION ALL
    select 'Gummo Marx' UNION ALL
    select 'Zeppo Marx'
    
select * from marxBrothers

delete marxBrothers
from marxBrothers,
    (
        select min(ident) as minIdent, name
        from marxBrothers m
        group by name
        having count(1) > 1
    ) as derived
where marxBrothers.name = derived.name
and ident > minIdent

select * from marxBrothers

drop table marxBrothers