SELECT num, com FROM TableA
WHERE num, com IN
    (
        SELECT count(*) AS co FROM TableA WHERE co > 1 GROUP BY num, com
    )

select ROW_NUMBER() OVER (PARTITION BY [num], com ORDER BY [num], com) as 'RowNumber', t1.*
    into ##TableA
    from TableA t1

delete t1
--select t1.*
from TableA  t1
join ##TableC t2
    on t2.[num]=t1.[num] and t2.com=t2.com
where t2.RowNumber > 1

select * from TableA;
with cte as (
    select *, row_number() over (partition by [num], com order by [num], com ) as Picker
    from TableA
    )
select cte
where Picker > 1

Msg 207, Level 16, State 1, Line 7
Invalid column name 'Picker'.
Msg 207, Level 16, State 1, Line 6
Invalid column name 'cte'.

select ROW_NUMBER() OVER (PARTITION BY num, com  ORDER BY identity_field) as 'RowNumber', t1.*
    into ##TableA
    from TableA t1

--delete t1
select t1.*
from TableA t1
join ##TableA t2
    on t2.identity_field=t1.identity_field
where t2.RowNumber > 1

--=======================================================
-- delete the duplicate records from table @t
-- keeping a single unit of each
-- marcelo miorelli 24-nov-2014
--=======================================================


--=======================================================
--create a table variable and insert records in it
-- just for this example
--=======================================================
declare @t table ([num] int, com varbinary(512) )

insert into @t select 1, convert(varbinary(512), '6778981' )
insert into @t select 1, convert(varbinary(512), '6778981' )
insert into @t select 1, convert(varbinary(512), '6778982' )
insert into @t select 2, convert(varbinary(512), '6778982' )
insert into @t select 2, convert(varbinary(512), '6778982' )
insert into @t select 3, convert(varbinary(512), '6778982' )
insert into @t select 4, convert(varbinary(512), '6778982' )
insert into @t select 4, convert(varbinary(512), '6778982' )
insert into @t select 4, convert(varbinary(512), '6778982' )
insert into @t select 4, convert(varbinary(512), '6778982' )
insert into @t select 4, convert(varbinary(512), '6778983' )
insert into @t select 5, convert(varbinary(512), '6778983' )
insert into @t select 5, convert(varbinary(512), '6778983' )
insert into @t select 5, convert(varbinary(512), '6778983' )
insert into @t select 5, convert(varbinary(512), '6778983' )
insert into @t select 5, convert(varbinary(512), '6778984' )
insert into @t select 6, convert(varbinary(512), '6778984' )
insert into @t select 6, convert(varbinary(512), '6778984' )
insert into @t select 6, convert(varbinary(512), '6778985' )
insert into @t select 7, convert(varbinary(512), '6778985' )
insert into @t select 7, convert(varbinary(512), '6778985' )
insert into @t select 8, convert(varbinary(512), '6778985' )
insert into @t select 8, convert(varbinary(512), '6778985' )
insert into @t select 9, convert(varbinary(512), '6778985' )
insert into @t select 9, convert(varbinary(512), '6778986' )
insert into @t select 9, convert(varbinary(512), '6778986' )
insert into @t select 9, convert(varbinary(512), '6778986' )
insert into @t select 9, convert(varbinary(512), '6778986' )

--=======================================================
-- this is going to show the table before the deletes
--=======================================================
select * from @t


--=======================================================
-- this deletes the duplicates - leaving only 1 of each
--=======================================================
; with cte as (
    select *
        , row_number() over (partition by [num],com  order by [num],com ) as Picker
    from @t
    )
delete cte
where Picker > 1


--=======================================================
-- this shows the table after the deletion - without the deletes
--=======================================================
select * from @t