本帖最後由 d-snake 於 2013-6-28 12:16 編輯
something like this:
select t.name, t.year, sum(t1.count1), sum(t2.count2), sum(t3.count3)
from
(select name1 [name], year1 [year] from table1
union
select name2, year2 from table2
union
select name3, year3 from table3) t
left join table1 t1 on t.name=t1.name1 and t.year=t1.year1
left join table2 t2 on t.name=t2.name2 and t.year=t2.year2
left join table3 t3 on t.name=t3.name3 and t.year=t3.year3
group by t.name, t.year
order by t.name, t.year |