select * from( select distinct customer_id, dense_rank()over( order by customer_id asc) rn_low, dense_rank()over( order by customer_id desc) rn_high from subscriptions as s ) t1 where rn_low <= 5 or rn_high <= 5 order by customer_id
select * from( select distinct customer_id, dense_rank()over( order by customer_id asc) rn_low, dense_rank()over( order by customer_id desc) rn_high from subscriptions as s ) t1 where rn_low <= 5 or rn_high <= 5 order by customer_id