0、select * from wmg_test; ? ? ---測(cè)試數(shù)據(jù)
1晦鞋、select v1,v2,sum(v2) over(order byv2) as sum ? ? --按照 v2排序蹲缠，累計(jì)n+n-1+....+1
from wmg_test;
2棺克、select v1,v2,sum(v2) over(partition by v1order by?v2) as sum ? ? --先分組，組內(nèi)在進(jìn)行 1 中的操作
from wmg_test;
3线定、select v1,v2,sum(v2) over(partition by v1 order byv1) as sum ? ---穩(wěn)定排序
from wmg_test;
4娜谊、select v1,v2,sum(v2) over(partition by v1) as sum ? ?--相同key的進(jìn)行回填處理
from wmg_test;
5、selectdistinct?v1,sum_01 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?--取一條
from (
select v1,sum(v2) over(partition by v1) as sum_01
from wmg_test
) a;
6斤讥、當(dāng)然也可以逆序累加纱皆，只需order by desc 即可
總結(jié)區(qū)別：group by 和partition by的區(qū)別
group 單純分組
partition 也能分組，但還具備累計(jì)的功能
