Ok, da minha resposta anterior do tópico MySql Single Table, selecione os últimos 7 dias e inclua linhas vazias
Aqui o que você pode fazer para tornar a seleção de data dinâmica
select
t1.attempt_date,
coalesce(SUM(t1.attempt_count+t2.attempt_count), 0) AS attempt_count
from
(
select DATE_FORMAT(a.Date,'%Y/%m/%d') as attempt_date,
'0' as attempt_count
from (
select curdate() - INTERVAL (a.a + (10 * b.a) + (100 * c.a)) DAY as Date
from (select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) as a
cross join (select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) as b
cross join (select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) as c
) a
where a.Date BETWEEN NOW() - INTERVAL 7 DAY AND NOW()
)t1
left join
(
SELECT DATE_FORMAT(attempt_date,'%Y/%m/%d') AS attempt_date,
COUNT(*) AS attempt_count
FROM users_attempts
WHERE DATE_SUB(attempt_date, INTERVAL 1 DAY) > DATE_SUB(DATE(NOW()), INTERVAL 1 WEEK)
GROUP BY DAY(attempt_date) DESC
)t2
on t2.attempt_date = t1.attempt_date
group by DAY(t1.attempt_date)
order by t1.attempt_date desc;
DEMO
