declare @t table ( col1 varchar(6), col2 varchar(6), col3 varchar(6), col4 varchar(6) )
insert into @t
values ( 'df', '3', 'dre gt', '87' )
, ( 'fr', '5', 'dre gt', null )
, ( 'df', '3', 'frt', null )
, ( 'dd', null, 'gttr', null )
, ( '3e', '3', '56t', null );

with cte
as
(
select row_number() over ( partition by col order by val ) id, * from
(
select distinct * from @t t
unpivot ( val for col in ( col1, col2, col3, col4 ) ) up
) t
)
select pv.col1, pv.col2, pv.col3, pv.col4 from cte
pivot ( max(val) for col in ( [col1], [col2], [col3], [col4] ) ) pv

col1   col2   col3   col4
------ ------ ------ ------
3e     3      56t    87
dd     5      dre gt NULL
df     NULL   frt    NULL
fr     NULL   gttr   NULL