Hide ( masking ) credit card numbers in SQL Server

This way

declare @t table (card_no varchar(20))
insert into @t
select 1245788956231589

select substring(card_no, 13, 4) as card_no from @t

O/P 1589

declare @t table (card_no varchar(20))
insert into @t
select 1245788956231589

select 'xxxxxxxxxxxx' + substring(card_no, 13, 4) as card_no from @t

O/P xxxxxxxxxxxx1589