where (Names is null or Names = '' or names = 'john')

with t as 
(select  'john' as Names, date() - 1 as DATES
union all
select  'smith' as Names, date() - 2 as DATES
union all
select  null as Names, date() - 3 as DATES
union all
select  '' as Names, date() - 4 as DATES
union all
select  'john' as Names, date() - 5 as DATES
)
select Names,DATES from t
where Names is null or Names = '' or names = 'john'

Names	DATES
john	2015
	2013
	2012
john	2011