พี่ ๆ ครับ!!! ขอความช่วยเหลืออีกครั้งครับ เรื่องการหาข้อมูลย้อนหลัง

select nm,st,en,department.department_nameEN,
sum(corrective_time+cr_load_time)as dt,COUNT(department_id) as occ
from downtime tb1
left join department on downtime.department_id=department.department_id 
inner join (
	select 'curweek' nm, DATE_SUB('2015-10-26', interval 6 day) st, '2015-10-26' en union all
	select 'retro1week', DATE_SUB('2015-10-26', interval 13 day), DATE_SUB('2015-10-26', interval 7 day) union all
	select 'retro2week', DATE_SUB('2015-10-26', interval 20 day), DATE_SUB('2015-10-26', interval 14 day) union all
	select 'retro3week', DATE_SUB('2015-10-26', interval 27 day), DATE_SUB('2015-10-26', interval 21 day)

) tb2


on tb1.downtime_date between tb2.st and tb2.en 

where plan='Unplan' and department_id='10' 
group by tb2.nm,tb1.department_id